The technology of coherent tracking based on signal beam nutation is presented in the paper. The working principle and advantage of the technology are analyzed. We provided the optical axis error detection algorithm and the selection method of nutation parameter. A simulation model of coherent tracking system was built, and the simulation results show that when half of the nutation angle is between 0.463 and 2 µrad, the degradation of the receiving sensitivity is less than 1 dB and the noise equivalent angle (NEA) is less than 0.02 μrad. When the nutation frequency is better than 10 kHz, the coherent tracking system can compensate vibration influence of some common satellite platform. The technology provides a new thought for free-space optical communication system design.