Photon heterodyne detection is a new detection technology combining heterodyne with photon counting and laser heterodyne principle. The photon counter which has single-photon detection capability is adopted as the detector, which greatly improves the sensitivity of photon heterodyne detection. In this paper, the physical model of photonic heterodyne detection is established, the design of photonic heterodyne lidar system is completed, and the velocity verification experiment is carried out. The experiment results show that the photon heterodynes velocity measurement technology can obtain target velocity information under the condition of strong background noise, and the accuracy of the velocity measurement is up to 0.005m/s.