Abstract: For the degradation characteristic of capacitor bank used in high power laser energy module, a reliability assessment method based on compound Poisson process is proposed and the parameters of the model are obtained by moment estimation method. The reliability index, such as average degradation, reliability and average life are estimated by Bootstrap simulation method. A numerical example is given to illustrate the effectivity of the method. Compared with traditional reliability assessment method based on life data, the proposed one based on capacitor degradation information can give objective results with scarce life data or even zero failures.