A set of forceapplying mechanism was designed, on the basis of the development of a testing stand of precision preservation of rolling functional components. The stresses of workbench in vertical milling process were simulated, and dynamic test of performance parameters was completed by controlling the mechanism. A mechanical model was established, and by making use of the principle of the force and moment equal to deduce the functional relationships between the simulated force of mechanism applied and the milling force. It was found that when the feed direction of milling cutter was mutated, the simulated force was also mutated through analysis of the relationships. The mutation of simulated force was not be able to achieved by the forceapplying mechanism. It was verified that rounded corners was added to eliminate mutation in the position of feed direction mutated. By using VB to complete the program design of the simulated force and torque changed along with time display interface, users were made to understand the change law intuitively. Operators can achieve the functional control of testing stand by the established system interface.