A temperature monitoring system for mechanical press’s bearing is presented. As multipoints of the cranks need to be monitored, the system is based on RS485 BUS, which is a distributed, real-time and reliable temperature monitoring net. It consists of the temperature monitoring sub module and the master module. The sub module gets temperature data via thermocouple and MAX6675. The master module controls the whole system with an ARM IC. The system can judge whether the temperature of bearing has exceed the limited value or the temperature is rising too fast, and send alarm signal to stop the press in those cases. Configuring this temperature monitoring system to the large or medium scale mechanical press can avoid the accident like bearing-burnt effectively.