Taking that the slide block in planar six-bar linkage is at the minimum rate fluctuation in working stroke for the pursuit of goals, and taking the existence of the crank and good transmission property for constraint conditions, a mathematical model of optimal design is set up and optimization design calculation is done by the application of the constrained variable metric optimization algorithm to obtain the mechanism size parameters. In Solid-Works software the three-dimensional model of assembly for the mechanism is built, and by using COSMOS-Motion plug-ins the motion simulation is done to put out the kinematic animation video, lines and other sports information, which provide a visual way for the optimal design of planar linkage. Simultaneously the above can be used to test or to determine the mathematical model of the mechanism optimum design, the correctness and rationality of the program design and the calculation results, and also provide a reference for the simulation design of other mechanisms.