A method for calculating the beam blockage coefficients is suggested,which uses the average value in a range bin to calculate the beam blockage coefficients.By processing the E00 terrain data of Hefei,comparisons between the average value method and the maximum value method has been made.Results show that the beam blockage coefficients calculated by the average value method are smaller than those by the maximum value method;the maximum reduction of the partial occulation correction of each range bin reaches 2dBZ;the number of range bins of 1.5 degree in the construction of the hybrid scan decreases by 44%;and the accuracy demand of input terrain data also decreases from 1:250000 to 1:500000.