The pressure shell is an important component that guaranteed the safety of the deep-sea submersible and staff. It is composed of Ti alloy shell and PMMA inspection window. The mechanical property of Ti alloy is stable, but the failure mechanism of PMMA is complicated. There is the lack of mature numerical technique and design method which can explore the effect of the damage evolution and post-buckling behaviors of PMMA inspection window. In this paper, Gurson plasticity model is employed to study the failure behaviors of inspection window by considering the influence of void growth of materials. The effects of friction coefficient and window thickness on the failure mechanisms of structures are discussed. This work provides a theoretical support for the design and safety evalution of PMMA inspection window.