The structure of the static labyrinth end cover outside the bearing seat of the short stress line rolling mill was optimized, so as to reduce the quality of the end cover and improve the strength and rigidity of the end cover.Reducing the quality and maximum stress and strain of the static labyrinth end cover was taken as the optimization objectives, Creo was used to establish the parametric model of the end cover, ANSYS Workbench was used for static analysis, response surface model was constructed and sensitivity analysis was carried out, finally MOGA algorithm was used to solve the optimal design parameters of the end cover.After optimization, compared with the initial value, the end cap mass decreases by 16.58%, the equivalent stress decreases by 22.10%, and the equivalent elastic strain decreases by 20.39%.So the light weight of the end cover is realized, the design strength and rigidity are improved. It provides references for the design optimization of the short stress line rolling mill in the future.