The software PRO/E was adopted to create 3D solid model of the hydraulic excavator work device. Then established the virtual prototype after added restrictions by which the model imported to the software of ADAMS. The force curves of several main articulated points were obtained through the dynamics simulation by which the step function of the cylinder displacement, the step function of the force of the bucket tooth tip, the step function of the material gravity was caculated. The results has provided the basis for the strength analysis and structural optimization of the hydraulic excavator working device. The simulation test for the bucket arm cylinder of virtual prototype maximum digging force was accomplished by utilizing the principle of analog dynamometer. Then calculate the bucket arm cylinder maximum digging force, and the comparative analysis between the calculation results and the simulation results was completed. The research has provided the new avenue for the test of the excavator digging force.