In the production of terahertz Micro-Electro-Mechanical Systems(MEMS) filter, every error caused by the process could affect the performance of the filter, and its index will not meet the design requirements. In order to make the qualified filter, this paper analyzes the size and parameters which could affect the performance of the filter, seeks the relation between parameters and performance, finally contrasts and analyzes the simulation and measurement aiming to propose the solutions. The yield and performance parameters of terahertz MEMS filter have been improved.