Numerical analysis method of membrane secondary buckling was developed.Arbitrary initial flaw was introduced into membrane by applying outside disturbance,and the phenomenon of membrane secondary buckling was analyzed.It is indicated that in the process of membrane post-buckling,the phenomenon of membrane secondary buckling appears because of initial flaw,wrinkle configuration is instable,and new wrinkles are produced.Post-buckling equilibrium path presents the multistage characteristic.In the case of different initial flaws and loading processes,the phenomenon of continuous secondary buckling emerges in the process of membrane post-buckling.It is concluded that membrane can be stable or not in the course of secondary buckling,which depends on initial flaw and loading process.