In this paper, the problem of multiple antennas mounted on platform is analyzed using method of moment in the MPI parallel environment. The approach of the matrix filling and solving by looping over column is described, due to the characteristics of Gauss elimination method, which can save data communicating time between processors. The patterns of power radiation in three planes of vehicular multiple antennas are calculated by the method using different numbers of processors. The results show that parallel computation can reduce computing time and memory requirements of each processor to the original's 1/process_num(processors number).