With the rapid development of economy, the distributed power supply (DG) is becoming more and more popular as a new, environmentally friendly and efficient power generation form.This paper focuses on the analysis of influence of distributed power grid to the traditional current protection of distribution network, using PSCAD / EMTDC simulation software to verify the effects of the different distributed power supply capacity and the different access location of each segment current protection in distribution network .It proposed a kind of distribution network specific sector of the access method of minimum short-circuit current.In the analysis of the DG grid based augumentation and drain currents of short-circuit current, the paper put forward a kind of no effect on the specific segment of the current protection of the optimal access mode, and the correctness of the method is verified by theoretical analysis and simulation modeling.