Abstract: In order to measure the speed of high moving object and make it intuitive to visual, we use non- contact mixing technology to measure velocity. The light which from semiconductor laser is divided by coupler into two beams, then it hits onto the surface of variable motion object successively. The two beams of light produce Doppler frequency shift due to optical Doppler effect, and finally form mixing in the coupler＇s exit. After mixing, it forms a beat frequency signal, then the signal is detected by APD, thus we can get a perfect voltage signal after it get through the amplification filter circuit, which contains the speed in formation. After that, the signal which through ARM is used for FFT analysis processing, eventually the speed curve is directly displayed in the LCD screen, so the velocity measurements of the high speed moving object come into realize.