In this paper, the composite lining total safety factor design method based on load structure model was established, and the influence of different section shapes on safety was studied. The conclusions are as follows. (1) The representative value of surrounding rock pressure based on the elastoplastic theory is used as the design load, which is suitable for safety and economy. (2) The load structure models established in this paper can calculate the safety factors of shotcrete layer, bolt-surrounding rock bearing arch, anchor bolt and secondary lining, and can obtain the total safety factors of tunnel construction and operation period. (3) The height-span ratio can significantly affect the safety factor. (4) The influence of tunnel depth on surrounding rock pressure and safety factor is relatively large. It is suggested that the corresponding supporting parameters should be adopted according to different burial depths, so as to improve the economy.