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In order to achieve the precise motion of a compound bridge-type micro-platform, an optimization model based on its dynamic characteristics was presented and the optimization design of structure parameters was carried out. The kinematic, stiffness and strength characteristics of the platform were derived by using the virtual work principle. The pseudo-rigid-body method and Lagrange equation were applied to establish the dynamic model. All proposed model is based on the structural parameters as the independent variables in the closed form, and it can provide the theoretical model for the optimization design. By comparing the theoretical model and FEA, the results show that the errors are within 6.0%～9.3%, which illustrates the proposed feature models are correct and precise. According to the closed-form natural frequency and amplification ratio, the sensitivity of this model with respect to structural parameters was analyzed, and then the design variables were chosen, which have greater impact on the dynamic properties of the platform. At last, the optimal model was proposed as the maximum natural frequency and amplification factor for the objective and the hinge strength, input stiffness, and geometric dimensions for constraints. The results show that higher natural frequency and more amplification factor are obtained from the optimum platform.So the proposed optimum platform can meet the design requirement.