In order to solve the problem of low computational efficiency caused by the huge number of mesh and difficult control of the details in the electromagnetic calculation preprocessing of MMS, a novel fast generation method of electromagnetic model of MMS based on MOM is proposed in this paper. Through the merging and subdivision of multi-layer two-dimensional geometric structures, they are grown into volume grids, and through the classification, replication and movement of grids, the electromagnetic model of MMS is quickly generated.