As the investigation deepened, it is necessary to measure the velocity of the object in an array with large quantities of points or in a covered area, in the field of explosion and shock waves physics, intense laser, et al. The operational principle and topology of photonic Doppler velocimetry were introduced, the transformation of power in optical fiber link was computed in detail, and the maximum number of channel was analyzed for multi-channel photonic Doppler velocimetry. According to the analysis, a 8-channel photonic Doppler velocimetry which can measuring 8 targets′velocity simultaneously, is assembled on the basis of the optical Doppler effects, and the velocity of the explosively driven metal plate was tested by the proposed velocimetry. The experimental results show that the velocities of the steel flyer plates and the lead granules are measured well, with the poor receiving efficiency. The research results will provide a valuable reference for the practical application of the velocimetry to measure a large number of targets′velocity simultaneously.