This paper presents the electromechanical system modeling of a direct-drive precision positioning XY table used for wire bonding. The XY table is directly driven by voice coil actuator (VCA) and therefore the equivalent circuit of VCA was built to construct the co-simulation platform of electromechanical system. By use of finite element analysis (FEA) and co-simulation method based on ADAMS and MATLAB/SIMULINK software, the spring as the key component in the decoupling mechanism was optimized and the matching law of stiffness and preload was given. The mechanical model of decoupling mechanism was then built up and the matching law was validated by theoretical analysis. The damp-spring-mass system of y-axis table further illustrated the matching law. For the complex electromechanical coupling system, the method of co-simulation could reflect the actual properties of system better compared with the oversimplified analytical model. The achieved results would be helpful to the dynamic design of the kind of manufacturing equipment and provide theoretical guidance for the control system development and testing.