Based on the WINDOWS system, the fast parallel MATLAB algorithm is used in calculating the RCS pattern of perfect electric conductor (PEC) with the method of moments (MoM). The computation of the impedance matrix and its inverse matrix is divided to the parallel computers. Each computer will finish its tasks. Meanwhile the necessary data are exchanged in the sharing space built at the basis of local area network. All the numerical examples prove that the calculated speed of the new technique is quicker and is able to deal with the problem of the largely electric object, which is unable to be calculated by a personal computer.