A control system of precision machine tool was designed with STM32 as its hardware foundation and LabVIEW as its programming language. Hardware composition and design of software were mainly discussed. The voice coil motor provided power to the platform. Optical encoder Mercury3000 was the measuring device. The quadrature signal of the encoder was converted into actual displacement as feedback signal for closed loop control system. The manmachine interface developed by LabVIEW had the functions of data acquisition，storage，playback and downloading control parameters. The interface was friendly and easy to operate. The overall design scheme had good promotional value.