Setting the modal test results as the object parameters, a refining approach for the dynamical modeling of a bolted printed circuit board assembly (BPCBA) is proposed in this paper based on ANSYS optimization design. Firstly, the sensitivities of the eigenvalues of a BPCBA to material parameters are calculated by using probabilistic design system (PDS) through ANSYS software. Secondly, according to the results of sensitivity analysis and the modeling error around the area of bolted connection, the material parameters of the BPCBA model are modified by using ANSYS optimization design method. Finally, the validity of the updated parameters are verified by comparing the natural frequencies of the BPCBA at different boundary conditions. The result shows that the accuracy of the model is significantly improved by optimization design method based on sensitivity analysis and modeling error.