Aiming at the problem of classroom ambient air quality, a fuzzy AQI monitoring management system for classrooms based on the IoT technology is designed. A monitoring platform integrating multiple air quality sensors and a fresh air conditioning system is constructed based on STM32, and the air quality data transmission is completed through TCP/IP、MQTT and HTTP protocols; by selecting five indicators of CO2, VOC, formaldehyde, PM2.5 and PM10 in classroom air quality, a Fuzzy Air Quality Index (FAQI) evaluation method is designed based on Fuzzy inference system; on this basis, Java Web/database technology and Vue.js framework are used to design background management system and APP, respectively, which realizes the real-time display of classroom air quality and stable control of the fresh air system. Practical test results show that the system runs stably, can effectively monitor and control the air quality in classrooms in real time, thus has certain promotion value.