The human body has its origin, just as wood has its root and water has its source. The kidneys are the root of vitality, and the spleen is the source of vitality. In other words, “the kidney is the root of innate nature, and the spleen is the root of acquired nature”. “The kidney is the root of the congenital, the spleen is the root of the acquired”, which is mainly reflected in two aspects of physiology and pathology: a. Physiologically, the spleen and kidneys help each other, the shape is full of body health 1. The kidneys are the main reservoir of essence, and the essence it collects includes the innate essence and the acquired essence. The kidney’s essence governs and regulates the growth and development of the human body, the maturation of reproductive functions and the physiological functions of the human body.2. “The spleen is the essence of the latter day” means that the human being is based on the grain, i.e. “if the grain is safe, it is safe, if it is not, it is dead”. Once a person is born, the internal organs of the human body need sufficient material and energy for functional activities and growth and development, and the water and grain essence produced by the diet is the main source of nutrients needed to maintain life activities since birth. The spleen is the main organ of transportation and transformation, and the stomach is the main organ of reception, both of which are “officials of the granary”. After the food is cooked and ground by the stomach, the essence is absorbed by the spleen, transferred to the lungs and dispersed throughout the body, nourishing the five viscera and six bowels and nourishing the limbs and bones.3 The kidneys store essence, which is the origin of life; the spleen is responsible for transportation and transformation, producing blood, which is the source of qi and blood. The first and second days complement each other and promote each other. The first day warms and stimulates the second day, the second day replenishes and nurtures the first day, the first day helps the second day, the second day helps the first day.4. The essence of the kidney depends on the cultivation and enrichment of the water and grain essence in order to constantly fill and mature, while the spleen and stomach transform the water and grain essence with the help of the warmth of the kidney yang. The first and second days are healthy and abundant in order to maintain the normal vital activities of the body. If the kidney is not strong enough to warm the spleen, the spleen will become weak; if the spleen is weak for a long time, the kidney will become weak, and the kidney will become weak, resulting in a deficiency of both the spleen and the kidney. In short, the congenital and the acquired are mutually supportive of each other, as the human being is born from the congenital and the human being is born from the acquired; the kidney essence is nourished by the transportation of the spleen, and the transportation of the spleen is warmed by the kidney yang. Both are closely related physiologically and pathologically, and the congenital and postnatal are complementary to each other, together completing the complex life activities of the human body.