Integral inference method for multi-state type-Ⅱcensored data is presented, which is used to evaluate the rupture life of composite material. The best unbiased estimators for the model parameters, the standard deviation and their covariance are also given. The confidence limits of the acceleration equation and the confidence intervals of percentiles for Weibull distribution are discussed in detail. According to the presented method, the experimental information of accelerated rupture life is fully exploited, and the cross information among test data in different stresses are analyzed as an integration.So its information quantity is much bigger than traditional group test method. The method provides a feasible and effective approach to rupture life evaluation and reliability estimation of composite material.