With the rapid development of optical fiber technology, the allfiber Doppler lidar has been used in the wind detecting. In order to maximize the benefits of the coherent Doppler lidar, the basic principles and structure of the Doppler lidar are described for the lidar data user and operators. The 532nm visible laser Doppler measurement system was built in the lab based on the Michelson interferometer principle, and the accurate speed of the wheel is gained. The principles, structure, and velocity inversion of the laser coherent velocity measurement system are displayed directly. In addition, the allfiber velocity measurement system based on 1550nm laser was set up in the lab, through a great number of observation experiments. When the speed of the wheel is 2.9 m/s and 4.8 m/s, the system errors of the speed is -001 m/s and 0.04 m/s and the standard deviation is 0.08 m/s and 0.1 m/s, respectively. The results show that the speed measured by the allfiler 1550nm laser velocity measurement system is credible.