The main function of turning linkage of automobile is to realize the ideal relations of turn angle of the internal and external wheels when vehicles steering. At present the main methods on design computing and verifying turning linkage have still been the planar graphing and analysis method, therefore it is very important to adopt optimization methods to design the steering linkage. Being satisfied with the Ackerman theory steering characteristics and boundary constraints, considering the ideal relationship of steering angles between external and internal wheels in steering linkage to ensure motion accuracy of automobile, optimization model of turning linkage is established. Then the objective function with penalty terms is built by penalty strategy with addition type, so the constrained optimization is transformed into the unconstrained optimization. The simulated annealing algorithm is adopted to optimize turning linkage of automobile, so that optimization process was simplified and the global optimal solution is ensured reliably.