The optimal design of the steering mechanism of a pure rolling automobile has always been one of the important goals pursued by automobile designers. If the parameters of the steering mechanism are designed reasonably, it can effectively reduce the wear of the tires during the turning process of the automobile. This paper proposes a method to quickly optimize the design of the steering mechanism of an automobile, which can quickly find the basic parameters under certain conditions, which is the cumulative sum of the absolute difference between the ideal rack length and the actual rack length required for pure rolling. Research has shown that the bottom angle of the steering knuckle arm is the most sensitive to the changing of the rack length. The length of the steering knuckle arm has an exact optimal solution. Through parameter optimization, the traditional design scheme can play its full potential. A MATLAB program on the parameterized optimization of rack and pinion steering mechanism is written to provide a reference for this kind of steering mechanism design.