Abstract: To determine the multi-performance degradation characteristics of the spacecraft DC/DC power supply, this paper proposes a life evaluation method based on the accelerated multivariate performance degradation by using the Wiener process and the accelerated model to establish the accelerated performance degradation model. The multivariate performance degradation data are analyzed by the Copula function with consideration of the correlation between the performance degradation processes. A certain model of the DC/DC power supply is taken as an example. The activation energy of the product and the life estimation under the usage thermal profile are obtained based on the test data. This novel scheme provides a new approach of the life estimation for the spacecraft products which typically with small sample quantity and long life.