Abstract: The coal preparation plant has a complex environment, a large monitoring area, a large number of monitoring points, and the points are scattered. The manual fixed-point timing sampling method of environmental parameters has poor real-time performance and low data accuracy. The wired monitoring system is inconvenient deployed, has high costs and easily damaged lines. The wireless monitoring system based on NB-IoT and LoRa technology has insufficient network coverage. In order to solve the above problems, an environmental monitoring system of coal preparation plant based on cloud platform is designed using ZigBee wireless transmission technology. The system architecture, hardware and software design of monitoring nodes (terminal nodes, routing nodes, gateway nodes) and cloud-based data management software design scheme are introduced. The system collects and processes the environmental parameters of the coal preparation plant in real time through the terminal nodes. The routing nodes summarize the monitoring data and forward them to the gateway nodes. Then the gateway nodes encapsulate the data and upload them to the cloud platform server via Ethernet. And the cloud data management software realizes data storage, analysis and display. The test results show that the system is stable in operation, accurate in data transmission, and can realize the functions of real-time monitoring and warning of environmental parameters and historical data query of coal preparation plant.