Runny nose is a common symptom of the nose, and different nasal diseases can appear with different nasal characteristics. Clear nasal discharge is thin and transparent, like clear water, which is mostly seen in the early stage of cold and flu and allergic rhinitis attack. It should be treated separately according to different causes. Allergic rhinitis can be diagnosed by medical history and symptoms. Generally, clear runny nose is accompanied by nasal itching, sneezing and swelling of nasal mucosa. The fundamental measure is to understand the allergens that cause allergy in children and try to avoid them, common allergens include pollen, grass, mold, dust mites, etc. Wear masks when going out, and at the same time choose anti-allergic drugs, with antihistamines taking priority, which can be combined with physiological seawater nasal rinses and montelukast, and nasal spray hormone treatment can be considered if the symptoms are serious. Upper respiratory tract infection is usually accompanied by sneezing, nasal congestion, some manifestations of cough, dry throat, headache, hoarseness, severe cases may have fever, mild chills, headache and other manifestations, upper respiratory tract infection drugs currently there is no special drugs, symptomatic treatment is the main focus, at the same time, pay attention to rest, drink more water, keep indoor air circulation and prevent secondary bacterial infection. Enhance resistance and improve the body’s ability to adapt to adverse conditions. During the cold season or flu epidemic in winter, go to public places less often, isolate the sick well and disinfect the air in contaminated rooms.