Composition of resin temperature control and liquid level control system based on Atmega2560 microcontroller unit（ MCU） for mask image projection stereo lithography（ MIP-SL） is introduced

and hardware of temperature control system and liquid level system are described in detail. The working principle and interface circuit design of the temperature and distance measuring sensor

four-bit digital tube and the liquid crystal display（ LCD） are introduced respectively. Design flows of the main program of the system and the temperature control subsystem and liquid level measurement subsystem are described in detail. Through serial port graphics display tool

temperature curves under different adjusting parameters are observed and compared

and parameters setting of proportional integral differential（ PID） control algorithm of temperature control system are carried out

appropriate PID coefficient is determined

and the control algorithm is realized in MCU system

the temperature deviation is± 0. 35 ℃. At the same time. The rotational state of the peristaltic pump is displayed in real time by the serial port display tool

and the liquid level control algorithm is realized. The fluctuation of liquid level in the process of fabrication is kept below 0. 15 mm

which indicates the rationality and validity of the design of the control system.