The present invention relates to a scanning coherent laser imaging radar distance-controlling device and a method thereof, which relates to the field of laser radar control. The present invention solves a problem that the existing scanning coherent laser imaging radar distance-controlling device does not need to add an external controller to realize scanning control. The scanning coherent laser imaging radar distance-controlling device comprises an on-line programmable gate array FPGA, a digital-analog converter D/A, an active low-pass filter and a signal plastic power amplifier. The method is that: firstly, the frequency of a driving signal of a radar scanning librating mirror, the frequency of radar image data collection and the control time sequence of a radar supply system are ensured; parameter control words are generated according to the frequencies, and the parameter control words are output to each functional module; and the radar scanning librating mirror, the radar image data collection and the radar supply system are controlled to work finally. The present invention lays a good foundation for obtaining images with high quality applied to imaging analysis and identification.