In order to evaluate the reliability level of national defense weapons and equipment accurately, reliability assessment for complex system based on information fusion is proposed. According to information fusion theory, the information fusion method of expert experience information, components and subsystems information, and reliability growth information are discussed. The inheritance and diverse population of information sources are considered, the information fusion reliability assessment method containing inheritance factor is introduced. The reliability is verified by combining with system test information, and analyzed it by example. The analysis results show that the method evaluation is reasonable, the it has high application value in reliability engineering field.