This paper introduces the principle of coating machine, the system to AT89S52 microcontroller as the core, stepper motor, press the body, sensors and manmachine interface and other peripheral components. Software to Keil4 for the development environment, the use of C language development. Hardware to Altium Designer Summer 09 for the development environment, design schematics and PCB. Hardware and software design, the realization of stepper motor control, to achieve the stability of the coating machine speed control. Through the experimental study, to complete the coating machine motion control and display, while the coating machine to improve the accuracy of 30%, 40% reliability, fundamentally solve the problem of coating machine.