Considering the regulating and structural characteristics of electric-hydraulic speed governor, an optimization study on elastic connecting plates was conducted. Firstly, on the basis of accurate force analysis, static analysis was done for the initial design of connecting plates by using the finite element method. Then, the mathematical model of the optimization design was established, which took several geometrical dimensions near the connecting plate’s middle rabbets as design variables, larger deformation displacement of the middle part as the optimization objective, and high reliability and good response as the constraint condition. Finally, an optimization analysis was carried out for different configurations by using COSMOSWorks/OPTSTAR, the actual working condition of the connecting plate was simulated and the calculation precision of the finite element method was verified through the experiments. The analysis of the result revealed that after optimization, the connecting plate increased Z-axial deformation displacement of the connecting plate, which can effectively improve the plate’s regulating sensitivity and reliability in the system.