Abstract: The metallized film capacitor is one of the most important components of the inertial confinement fusion(ICF) facility. The reliability of the capacitor greatly influences the reliability and operational cost of the whole facility. Based on the analysis of the failure mechanism of the capacitor, we model the degradation process with Wiener process. The time-to-failure distribution is derived. A reliability assessment method combining performance degradation data and lifetime data is proposed. A precision analysis is made for both the proposed method and degradation data based reliability assessment method, using the precision analysis approach given in this paper. Results show that the proposed method has a better precision compared with the degradation data based method.