In order to select the optimal bridge deck structure, the voltage-displacement, stress and mirror flatness of four new folded beam bridge deck structures of Fabry-Perot(F-P) cavity tunable filters (with no holes, circular holes, square holes and diamond holes) were simulated using the multi-physics finite element COMSOL software. The results show that the displacement of the bridge deck with diamond holes is the largest under the same driving voltage. Meanwhile, the required driving voltage of the bridge with diamond holes is the smallest under the same displacement. The stress and flatness of the bridge with diamond holes can also meet the design requirements of filters. Then the filtering performance of the optimized folded beam bridge deck structure with diamond holes was analyzed by the Essential Macleod software. The results show that its filtering is excellent in the optical spectrum of 3~5μm tuning range, and can meet the requirements of low driving voltage and wide tuning range.