Abstract: This paper presents a new fault isolation scheme for distribution network with high penetration rate of DG, on the basis of comparing the memorial current phase. According to the same current phase information of the FTU of distribution line before the fault, the method gets the phase of current fault component on reference of the current phase before the fault. Fault isolation criterion is got by comparing the phase relationship between adjacent FTUs: if adjacent FTUs get the same phase of current, it's the external fault; otherwise the fault is internal one. Extensive simulations show that the scheme needs little communication traffic, need not to install voltage transformers. It is possible to solve fault isolation misjudgment and failure or other issues brought by the applying of the traditional fault isolation to active distribution network, and possess a good prospect of engineering application.