Abstract: Composite overwrapped pressure vesseles（COPV）are widely applied to space system.Finite element model of COPV and its liner are established by ANSYS finite element program.In the modeling,the total of filament wind ing layers are handled as composite laminate,with considering variational thickness and wrap angle of every unidirection al layer of the domes.Eigen buckling and nonlinear buckling finite element equations of the integral vessel are established.Buckling cal-culation of COPV and its liner are respectively made,and buckling modal shapes and the critical outer pressure are obtained。