Abstract. Temperature is one of the most basic environmental parameters. The measurement and control of temperature are of great significance and application value in people's daily life and industrial production. So, this paper realizes the temperature monitoring system based on STC MCU. The DS18B20 temperature sensor is used in the hardware, and the display circuit, temperature overrun alarm circuit and key input circuit are set up. Finally, according to the design of the system, the temperature measurement accuracy and stability are tested, and the results show that the measurement error of the system can be controlled within 1℃. in addition, the system has the characteristics of simple measurement, low cost and easy to use, good market prospects.