The interdigital MEMS filter is an interdigital structure filter fabricated by using the technology of MEMS. Aiming at the problems of slow speed and taking up large computational resources in the electromagnetic optimization algorithm of the interdigital MEMS filter, an optimization design method of the interdigital MEMS filter is studied in this paper. The ADS and HFSS software are used to establish the circuit structure model and threedimensional structure EM model of the filters which are applied to the coarse simulation and accurate simulation for the aggressive space mapping algorithm respectively, and the optimized design of a Kuband filter has been completed after only 5 accurate simulations. The results show that the designed filter has the center frequency of 14 GHz, top loss of 1.6 dB and -1 dB bandwidth of 2.2 GHz, which satisfy the design specifications. At the same time, the feasibility of the optimized design method is verified.