Abstract: The terrain fluctuation is one of the most important error sources of radar observation,which will cause the data distortion at and behind the observing site on the radar beam path. A method of radar beam blockage coefficient information based on SRTM data for analyzing objectively the weather radar stations is developed. According to the geographic information of the selected radar station and its periphery,it can calculate the beam blockage coefficient. It are utilized to analyze the valid mosaic data region and to correct the beam occultation. It improves accuracy of radar data. This paper introduces computing principles and methods of beam blockage coefficient and analysis how beam blockage affect the radar echo intensity using the clear-air echo characteristic. An algorithm is developed to compute probability distribution of radar echo. To compared and analyzed the beam blockage coefficient and different elevation statistical probability distribution of radar echo,it verified the correctness of the beam blockage coefficient.