The research is about power system reliability issues when photovoltaic-battery micro grid accesses. First of all, we analysis the characteristics of photovoltaic-battery micro grid. Then we analysis the effect of photovoltaic-battery micro grid’s location and operation mode to the the reliability of the distribution network. And the research establishs a reliability evaluation model of the distribution network including photovoltaic-battery micro grid based on the minimum circuit method, and verifys these in a typical system structure. The research shows that the access of photovoltaic-battery micro grid in the power system can ascend voltage and reduce network loss,and effectively improve it’s reliability. The evaluation model can be used to evaluate its reliability of distribution networkcan with photovoltaic-battery micro grid ,and it can be used in the improment of power system reliability.