Based on analyzing the primary factors influencing the sealing performance of knife-edge sealing structure, a uniform design numerical experimentation was performed using FEA software. The second-order polynomials which reflect the relation between design parameters and sealing capability were fitted using the simulation results. Multi-objective optimization model of effective sealing surface width and maximum contact pressure was established according to the optimization method for multiple objectives. Genetic algorithm was applied to seek the global optimization results, and a set of optimized design parameters were obtained. Finite element validation results showed that the optimized structure has better sealing performance.