As a big agricultural country, realizing agricultural modernization is the only way for development in China. In recent years, with the progress of agricultural science and technology and the development of rural economy, new generation technologies such as sensors and Internet of Things have provided a new model for the upgrading and innovation of traditional agriculture and the development of smart agriculture. Combining NB-IoT wireless communication technology and IoT cloud platform, this paper designs a new type of agricultural greenhouse environment monitoring system. This system is mainly composed of sensing module, data processing module, transmission module and application processing platform, the hardware circuit design includes STM32F103C8T6 data processing module, NB-IoT wireless communication module and various sensor interface circuit, and the software design includes acquisition terminal main program design, NB-IoT wireless communication design and sensor program design. It realizes real-time acquisition of air temperature and humidity, soil humidity, light, CO 2 concentration, PM2.5, wind speed and raindrop sensors in greenhouse, and establishes communication connection with IoT cloud platform through NB-IoT network.