In this paper

based on the kinematics and dynamic analysis of a spring actuator

the specifications of the breaking and closing velocity characteristic of vacuum circuit breaker are taken as constraints

the lengths of the linkages of the spring actuator and its tolerances are chosen as the optimization variables

and the materials costs of those linkages and its relative tolerances compose the multiple objection function.The optimization strategy integrated discredited random direction searching with complex algorithm is adopted for solving the optimal tolerance design problem.As the optimization results

the optimized nominal parameters of the components and their largest tolerances of the actuator are given automatically.When the component tolerances are within the optimum tolerance region

the breaking and closing characteristics are all satisfied.It proves to be a new optimization design strategy.