The laser coherence Dopplervelocity radar is used in field measurement,navigation and aircraft landing due to its high measurement accuracy,wide range and small power consumption.In order to test its speed accuracy,in this paper a speed generator is developed,and an accuracy test platform with high precision and large speed rangeis built.The accuracy of laser Doppler velocimetry was measured using the built test platform.The accuracy was 0.0383m/s at the speed of 105.8266m/s.The accuracy of laser Doppler velocimetry was analyzed,the FFT frequency was corrected by interpolation method,and the FFT processing method of pipeline,increasing sampling number and increasing sampling frequency are adopted to improve the speed accuracy.