In order to view the multi-channel pressure and Watt-hour meter's data of a supermarket's cold chain remotely and take measures in time when the cold chain system is abnormal, a monitoring alarm system for supermarket's cold chain based on STM32 was designed. The system converted the pressure signal into voltage signal through the pressure acquisition circuit, and the voltage signal was collected by the ADC of the STM32 microcontroller; and the data of the 4 Watt-hour meter's data was collected by the RS485 bus.，besides the system controlled the switch of field equipment by relay. STM32 microcontroller dealt with the collected data through the relevant algorithm and the results would be shown on the TFTLCD monitor at the scene, which was convenient to observe for field staff. The GPRS module transmitted the collected data to the host computer, which enabled users to view field data remotely. When the data was abnormal, the user would receive alarm messages and could control the field device by replying to the messages. Experiments showed that the system measured accurately and responded quickly and had better real-time performance, besides the system had advantage of low cost and reduced the workload of meter readers effectively, which ensured the safe operation of supermarket's cold chain system.