Abstract: In order to solve the problems of traditional constant temperature control in industrial and agricultural applications，such as low automation level，low precision and poor stability，an automatic control system based on novel fuzzy-PID ( Proportion Integration Differentiation) control theory is designed． STM32 microcontroller is used to collect temperature and control，matrix keyboard and LCD ( Liquid Crystal Display) screen are used as human-computer interaction equipment，the novel fuzzy-PID control algorithm is used to construct the fuzzy-PID controller，the parameter values of proportion，integration，differentiation are processed by iterative algorithm． The semiconductor chiller is heated by the corresponding PWM ( Pulse Width Modulation) high level duty ratio output current based on the control quantity． The experimental results show that the system can quickly collect the temperature data of the system and control the system in real time，stabilize the temperature of the system at the expected temperature，the absolute error of the system is 0． 1 ℃ in theory，the actual measurement error is 0． 5 ℃． The system could achieve a better automatic detection and control of temperature with reliable performance，and solve the above problems．

Key words: accurate, automation, novel fuzzy-proportion integration differentiation ( PID) control, iterative algorithm