In the noncoherent Doppler wind lidar system, the laser line width and frequency stability are two important factors influencing the accuracy of measurement results. The injection seeding technique method was used to obtain narrow linewidth of 532 nm lidar. The iodine filters as receiv frequency discriminators and lock the transmitter laser frequency. Using VB language writing instrument control program based on PID algorithm, the frequency of seed laser locked in iodine molecular absorption lines, which was 1 109 line of high reflection on the edge. The frequency stability was better then ±0.5 MHz for 4 h, the long-term frequency stability as 3.55×10^-9. Design the continuous light velocity measuring system, which concluded the cure about Doppler frequency shift and actual speed of chopped wave plate, the velocity error was less than 0.4 m/s. This also shows that the laser velocity measuring system can be calibrated on the lock the frequency of the whole system. This experiment also provides guidance significance for the construction of wind lidar.