This paper analyses the effects of DG supply to distribution network’s fault current, and proposes an improved protection scheme. The scheme utilizes the fault current characteristics of the DG distribution network, refers to the phase angle change of the current at both sides of the line, control from the beginning, to determine the fault between the main power supply and the DG access point. The request of current amplitude’s accuracy is not high, and it is not influenced by the system operation mode, simple and reliable; only the digital signal reflects the change direction of current phase angle and protection decision signal need to transmit, communication channel requirement is not high; only the current information collected before and after the fault is required, saving the voltage transformer and having a good economy for the distribution network. The simulation experiment proves its feasibility. This work is supported by National Natural Science Foundation of China (No. 51607110) and Natural Science Foundation of Shanghai (No. 14ZR1417600).