Objective Based on the student symptom monitoring system established by WeChat applet,the feasibility of early warning of infectious diseases in primary schools was discussed. Methods Based on the information construction of “intelligent disease control” in a county,a symptom monitoring system for students with mobile phone as the information collection terminal was established.Fever,cough,sore throat,nausea,vomiting,abdominal pain,diarrhea,rash,herpes,parotid gland swelling,fatigue,headache and myalgia were used as monitoring indicators,and threshold SMS warning was carried out on symptom data by means of class clustering retrieval. Results From February to June in 2023,a total of 360 medical institutions at the county,township and village levels were registered in the system.The system utilization rate of medical institutions was 100 %.There were 31 registered schools,and the utilization rate of the school system was 49.97 %.A total of 11 802 monitoring symptom information of 13 categories were reported,with fever (61.07 %),cough (15.67 % ) and sore throat (7.65 % ) as the main symptoms.The time trend of different symptoms was the same,with a peak in March.A total of 180 warning signals were issued by the system,of which 7 were investigated and confirmed as clustered outbreaks. Conclusion The student symptom monitoring system has a wide range of applicability at the grassroots level,and the monitoring data plays a good role in early detection of abnormal infectious diseases in schools.