Asthma is diverse and complex, which leaves many children undiagnosed or misdiagnosed in the early stages of asthma onset, which in turn delays treatment and leads to recurrent attacks and exacerbations. Children with asthma do not present with asthma from the beginning; there is usually a period of time when the precursor symptoms appear. The following can be used as early warning signs of asthma in children: 1. Repeated coughing for more than a month, mainly in the morning and at night, often with an irritating dry cough and not much sputum. 2. Irritating dry cough easily appears after exercise, inhalation of cold air or consumption of cold drinks. 3.Recurring chest tightness, which intensifies when you have a cold or after exercise. 4.Irritation to certain odors (such as decoration odors, toilet cleaners, perfumes, styling mousse, etc.), with sneezing and coughing. 5.Allergic to seafood, certain tropical fruits, some medications, or in infancy manifested as intolerance to eggs and milk powder (often manifested as crying, vomiting, diarrhea, severe and recurrent eczema, no weight gain). 6, there are frequent sneezing, runny nose, nasal congestion, nasal itching and other symptoms of allergic rhinitis, often manifested as shrugging, nose rubbing, nose picking. 7.Have a significant history of eczema. 8.Have a family history of allergy (need to ask relatives within three generations if they have allergic diseases). 9. Increased peripheral blood eosinophils. For children with the above-mentioned manifestations, community doctors must be highly alert to the possibility that they will develop asthma and should recommend them to go to a tertiary hospital for examination, diagnosis and treatment.