Abstract: Considering the complicacy,relevance,and low design efficiency in the conventional design of a MEMS phase shifter,an innovative idea,which adopts Hybrid Adaptive Mutation Particle Swarm Optimization,is proposed. Then,this new algorithm is applied to research the property of a MEMS phase shifter,which simplifies its design process. Co MParing with the conventional design,the new method can save plenty of time and show high property. Besides,the phase shifter can obtain phase shift from 0 to 90 deg and a high phase accuracy. The improved method can be applied to the design of MEMS phase shifter.