Acute left heart failure is a cardiac emergency with dyspnea, chest tightness, cough and shortness of breath as the main manifestations. It commonly occurs when myocardial infarction, myocarditis, sudden rise in blood pressure, rheumatic heart disease and infusion of fluids too fast or too much, and sometimes it can also be triggered by exertion, excitement, cold, sudden change in climate, pregnancy and childbirth on the basis of various existing heart diseases. Since this symptom often occurs suddenly at night, if the correct and timely on-site or home assistance can effectively relieve the symptoms, reduce the patient’s pain and create conditions for further rescue and treatment. The first step is to accurately determine whether the patient’s dyspnea is cardiogenic asthma in acute left heart failure rather than bronchial asthma. The two manifestations are “wheezing”, but the methods and principles of resuscitation are very different. How to distinguish the two as soon as possible without the presence of medical personnel? Simply put, besides referring to the past medical history, it is necessary to find out what is the relationship between the patient’s “wheezing” and body standing. In acute left heart failure, “wheezing” often occurs suddenly during sleep, and is significantly increased when lying down and reduced when sitting down; while the exacerbation and relief of bronchial asthma are not obvious in relation to the change of body position. The relationship between exacerbation and remission of bronchial asthma is not obvious. If the “wheezing” is definitely acute left heart failure, you should not use the various wheezing aerosols commonly used by asthmatic patients, nor should you take albuterol and other wheezing drugs orally, as these drugs can only aggravate the left heart failure and even lead to sudden death of the patient. Sublingual nitroglycerin, digestive pain and Kepone and other drugs can be taken. The key measure to resuscitate acute left heart failure at home is for the patient to take a sitting position, either on the edge of the bed or on a chair, with the legs naturally hanging down or on a small bench, with the upper body leaning forward. This position can effectively reduce the burden on the heart; at the same time, the diaphragm drops, so that lung capacity increases and respiratory distress is relieved. Patients with acute left heart failure often have a sense of near death, nervousness, accelerated heart rate and increased heart burden, which is very unfavorable to the patient. Family members should do their best to comfort the patient and eliminate their nervousness, which sometimes has unexpected effects. Oxygen can be given to the patient immediately if there are oxygen conditions at home, oxygen is best to go through the wetting bottle and then into the nasal cavity, if the water in the wetting bottle is poured out 30-40%, and then add an equal amount of alcohol, the effect will be better. It should be noted that only some of the mild left heart failure can be expected to be relieved by the above-mentioned methods of home assistance, while a considerable number of patients with acute left heart failure require home emergency care by a clinician in the hospital while 120 should be contacted promptly. The sitting position with legs down should be insisted on the way, and the patient should never be allowed to walk to the hospital reluctantly.