This paper focuses on the reliability evaluation of photovoltaic(PV) module products under accelerated degradation conditions. A method to estimate the pseudo failure life distribution of PV modules based on the Generalized Lambda Distribution(GLD) was proposed. Firstly, the determinative coefficient test method( R2) was used to select the best accelerated degradation path to obtain pseudo failure life values of samples. Then, the bootstrap method was taken to generate bootstrap samples to expand the sample group and to build a pseudo failure life distribution model based on GLD, which could truly reflect the pseudo failure life distribution of PV modules under different acceleration conditions without presetting the prior distribution, Finally, by taking accelerated performance degradation data of a 18 W small power Mono-Si silicon PV module as an example, the pseudo failure life distribution and reliability of PV modules were estimated under accelerated degradation conditions. The results show that this method obtains pseudo failure life distribution in accelerated degradation conditions, and reliability curves and the experimental data results fit well. Moreover, the absolute error of fitting curve is basically in 300 h, and the relative error is not more than 15%. These results meet the demand of engineering forecast precision.