Doppler lidar plays an important role in wind measurements and numerical weather prediction, and signal to noise ratio (SNR) is an important parameter to measure the system’s accuracy. Based on the first mobile Doppler lidar system in China which is developed by Ocean University of China in 2007, the SNR for sea surface wind measurements with four different repetition rates are simulated. Simulated and measured data are in good agreement. The results show that the lower laser frequency used in the lidar, the higher SNR obtained. According to the requirements for operational measurements, Doppler lidar requires relatively high laser repetition rate. It is recommended to select a laser with pulse repetition rate during 500～1000 Hz.