This theory was inferred from the physiopathological functions of the lung in the Nei Jing, and has been universally accepted through long-term practical testing. The first to clearly put forward the word “suzheng” and associated with the lung for the Qing Ye Tianshi’s “clinical guide to medical cases”: “the lung for the breathing of the gems a, in the highest position, by the internal organs of the Qing Qi, endowed with the body of the Qing suzheng, the main nature of the descending.” However, the understanding of “the lung is the main surrender” can be described as “benevolent, the wise man see wisdom. It is mostly interpreted by the Kangxi Dictionary, Guang Yun, and Li Ji as “to shrink, to converge, to kill, to draw, and to clear”. The function of the lungs is expressed in the following four aspects: First, it is to inhale the clear qi of nature and incorporate it into the kidneys. Second, it is to purge the lungs and the respiratory tract of foreign matter and keep the respiratory tract clean. Third, it is to distribute downward the clear qi inhaled and the fluid and water and grain essence transferred from the spleen to the lungs. Fourth, through the purification of the lung qi, “the lung qi is transferred to the large intestine to regulate water and fluids”. This article focuses on the nose in the function of “su”. The nose is the uppermost part of the respiratory tract and is connected to the lungs through the lung system. The lung qi penetrates the entire lung system and reaches the nasal orifices, which together perform the functions of “propagation” and “descent” of the lung qi. Su Wen? Yin Yang Ying Xiang Da Lun said: “The lung is the master of the nose …… in the orifice for the nose”, “Ling Shu? Five reads five makes chapter” said “the nose, the official of the lung also”. The lung is an internal organ, and the nose is one of the five organs. “The lungs are open to the nose”, the so-called orifice is “hole also, hole also, mouth also, through also”. This explains the close relationship between the nose and the lungs, which is interconnected, interdependent and mutually influential. Traditional medicine and modern medicine have different theories about physiology, pathogenesis, pathology and pharmacology, but the object of study is the same “human” in nature, and they share the same path. It is also one of the ideas to try to explore the combination of Chinese and Western medical theories. The dialectical relationship between anatomical structure, physiological function and clinical symptoms reflects the basic characteristics of disease occurrence and development (1). The nose, trachea and bronchus, and lung have continuity in the respiratory tract anatomy. The mucosa of the nasal respiratory area and the ductal parts of the trachea, bronchi and lungs are pseudocomplex ciliated columnar epithelium, and their mucosal layers have cup cells, plasma cells, and secretory glands; mast cells are distributed in the submucosa and around the capillaries. In terms of innervation, both are innervated by sympathetic and paired sympathetic nerves with the same mechanism of action. These common points form a close relationship between the nose and the lung in terms of physiopathology and mutual influence, which is perhaps one of the scientific essence of “the lung is open to the nose” and “the orifice is also through”. The nose is different from the trachea, bronchi and lungs in terms of anatomical location of the respiratory tract. The position of the nose is at the upper end of the trachea, bronchus and lungs. Due to the earth’s gravity, all normal or abnormal secretions are bound to move downward, and most of the mucus secreted in the nasal cavity, about 1 ~ 2 L per day, is eventually swallowed into the gastrointestinal tube. This is probably one of the meanings of the word “descending” in the term “sukding”. The resulting pathological changes can lead to respiratory and gastrointestinal diseases such as upper airway cough syndrome. The nose is located at the outermost part of the trachea, bronchi, and lungs, and is the window connecting the respiratory tract to the outside world, so called “the lungs are open to the nose” and “the nose is connected to the weather”. The resulting pathological changes can lead to respiratory diseases such as allergic rhinitis and asthma. Modern medicine believes that under normal conditions, people breathe 12-24 times per minute and inhale about 10,000 liters of gases of different temperatures and humidity containing dust and microorganisms every day. Due to its special position, the nose, as the first barrier of the human body, must perform the following functions: breathing, nasal resistance, olfaction, mucus cilia removal, filtration, air conditioning, immunity, perception and voice resonance. Among the functions related to the “su” are: 1, mucus cilia removal function of the nasal mucosa is mostly composed of pseudostratified ciliated columnar epithelium. The nasal mucus cilia transport system is mainly composed of the cilia on the surface of the respiratory tract and the mucus blanket above it. Ciliary oscillations provide direct impetus for mucus blanket movement. Non-soluble particles in the air are captured by the mucus blanket and moved toward the nasopharynx and larynx, and eventually swallowed into the gastrointestinal tract. In addition to the mucus cilia removal function, the nasal cavity also removes respiratory secretions backward and forward through forceful inspiratory and nose-blowing movements, respectively. This is probably the meaning of “lead” in Su. 2, air conditioning function (warming and humidification) nasal turbinates and septal mucosa in the rich blood supply, through conduction, convection and radiation and other ways to increase the temperature of the inhaled gas. So that the inhaled gas from the nostrils at about 20 ℃, to reach the trachea for close to the body temperature of 35 ℃. When the gas is exhaled out of the nasal cavity, 33% of the heat and moisture are retained on the surface of the nasal mucosa. To ensure the humidification and protection of the mucous membrane nasal mucosa produces a total of about 1 ~ 2 L of mucus per day, the water on the surface of the mucus blanket evaporates, making the gas humidity up to 75% ~ 80%. Change the dry, cold air, which is probably the meaning of “shrinkage, convergence” in the change in the su. 3.Filtering function The air contains a large amount of particulate matter, which can directly damage the lower respiratory tract and alveolar function after inhalation. The nasal vestibule in the nasal hair and the mucus blanket above the nasal mucosa can capture all the particulate matter with a diameter of 4μm or more. The “purity” of the gas exchange in the alveoli is fully guaranteed. This is probably the meaning of “clear” in Su. 4, immune function The immune function of the nasal mucosa is divided into specific immune function and non-specific immune function. The non-specific immune function includes the filtering function realized by the mucus cilia transport system, the inhaled microorganisms, irritants and allergens are captured by the mucus blanket and transported to the pharynx and swallowed, so as to be destroyed by the digestive enzymes in the digestive tract, meanwhile, the nasal secretions also contain immunoglobulins IgG, IgM and IgE, as well as enzymes (lysozyme, lactoferrin) and protective proteins (complement), which constitute the human body’s primary defense system. Another non-specific immune function is the inflammatory response, with vasodilation, increased capillary permeability, plasma extravasation, and neutrophil activation leading to nasal congestion and runny nose, which constitute the body’s secondary defense system. In addition, the release of factors associated with activated inflammatory cells excites nerve receptors, leading to nasal itching and sneezing. Specific immune functions include humoral and cellular immunity, which are responsible for the complete elimination of pathogens and the formation of immune memory (2). This is probably the meaning of “killing” in “su”. This “suing” defense of the nose constitutes the body’s first protective barrier, reflecting the role of the lung as the master of qi defense. The “suction and descent” is inseparable from the lung’s “propagation” function, Chinese medicine believes that “the right qi exists within, evil cannot dry”, “right qi “It is the “lung is the main qi, the main propagation, the upper transmission of zong qi in the nose” caused by. To sum up, the nose is the lung’s orifice, the lung’s loyal defender; the lung is the strong backbone of the nose against external evil.