Abstract: Based on the meteor radar, one can study the radiant distribution and the time variant of meteors, forecast the passage time of meteor showers, and also investigate space, and so on. Based on standard theory, the effects of main factors, such as ambipolar diffusion, the initial trail radius, the finite meteor velocity and the Pulse Repetition Frequency (PRF), on the radar echoes power at different radar frequencies and meteor velocities have been numerical analysis and calculated. The observation data of meteor decay time and the ambipolar diffusion coefficient are consistent with the theories. By analyzing the 571632 meteors observed by Kunming meteor radar, the height distribution of meteors model has been constructed, the result predicted by this model agrees with observation data at different months.