In order to investigate the influence of labyrinth seal structure parameters on the characteristics of leakage rate,The influence of the labyrinth seal structure parameters and their interaction on the leakage rate was numerically researched by quadratic regression orthogonal test.A reliable regression equation not lack of fit was established to optimize the structural parameters of the labyrinth seal.The results show that the depth of the seal cavity,the height of the boss,the thickness of the seal teeth and the tip clearance have great influence on the leakage rate,and the effect of the tip clearance on leakage is the most significant.The interaction among the four items has a certain impact on leakage rate,and there also exists the optimal structural parameters to minimize the leakage rate.According to the test,the regression equation has good significance and does not lack of fit.After optimized,the labyrinth seal has more entropy increase and more energy dissipation in the tip of seal teeth as well as has lower speed and smaller inertia effect in the cavity,therefore the optimized labyrinth seal has a better sealing performance.