Missile failure is the competition result of multi-components degradation failure and outburst failure. According to failure mode analysis, a missile competition failure model is presented. Aiming at the voltage testing data of missile key multi-components in storage time, the state space model is applied to integrate the multi-components voltage into whole missile degradation degree. The stochastic process models of Wiener, Gamma and inverse-Gaussian are used to fit the whole missile degradation degree data. Akaike information criterion is applied to determine the optimal stochastic process model. Missile outburst failure time is assumed to be Weibull distribution. The proportional risk model is used to build an outburst failure model with the degradation impact. Two-step maximum likelihood estimation is used to obtain the unknown parameter estimates. A numerical example with a set of missiles in storage is analyzed to verify the accuracy and the superiority of the presented model.