In order to solve the all fiber laser doppler homodyne detection optical path of the light energy loss, interference figure problem of low contrast and low signaltonoise ratio, this paper compares three kinds of allfiber laser Doppler homodyne detection optical path.Analysis of four light path and calculate the optical power of each optical fiber passive components in the total loss and the overall utilization rate of light path of light, some comparative experiments of three light path design, the optical power meter and plugin return loss instrument measured for three kinds of optical path of light power;Through observing three kinds of interference of light path photodetector output waveform, and calculated the interference figure contrast.The measured results show that the calculation results and experiment results, the optical path of the light energy loss is lower, the output of the doppler signal amplitude greatly, signal the higher signaltonoise ratio, the higher the contrast.