The designs to improve the problem such as large temperature fluctuations in polymerization reactor affect the quality of CH4. The slave computer MCU controls temperature sensor to detect temperature; the host computer PC monitors temperature of polymerization reactor, and draws a monitoring interface by Kingview. In order to control the temperature of polymerization reactor, the MCU uses Dahlin algorithm. Meanwhile, the system has real-time temperature displaying, recording, storing, alarming, serial communication and so on functions. Establishing the control system based on the PROTEUS simulation. Experiment shows that temperature is controlled at 200±3°C in the constant temperature phase, and it is superior to polymerization reactor required at 200±5°C.System Experiment Completely Meet the Requirement.