Due to the uncertainty energy resources, the distributed renewable energy supply usually leads to the highly unstable reliability of power system. For instance, power system reliability can be affected by the high penetration of large-scale wind turbine generators (WTG). Therefore, energy storage system (ESS) is usually installed with the distributed renewable energy generation to improve the power system reliability by smoothing out the fluctuations and improve the supply and demand balance. This paper aims to analyze the power system reliability by developing the multi-ESSs coordinated with WTGs model, which is each ESS linked with each WTG. The main indices for reliability evaluation are loss of load expectation, expected energy not served and energy index of reliability. Monte Carlo simulation method is used in this study. Furthermore, this paper demonstrates various sensitivity analysis of multi-ESSs model include the impact of various ESS capacity, peak load, WTG dispatch restriction index in China power system among case study. In addition, the capacity credit of WTG with multi-ESSs were evaluated in this study.