The connection of DG makes distribution network topology be changed from single-power radial network to complicated network with multi-power. Under such condition, traditional fault location algorithm is no longer applicable. To solve this problem, this paper proposes a new fault location algorithm based on fault current —— immune algorithm. First, according to the distribution network with DG, the fault current coding mode adapting to multiple distributed power supply and the switching function of multiple distributed power supply are constructed. Secondly, compared with the traditional genetic algorithm, the immune algorithm evaluates the individuals by calculating the affinity and concentration of the individual and increases the memory unit to ensure the diversity of the antibody during the evolution of the algorithm, thus avoiding the 'premature' convergence problem. Finally, through the Matlab modeling and simulation, it is proved that the algorithm is suitable for fault location of distribution network with distributed generation (DG), and has a certain speediness and fault tolerance. This work is supported by National Natural Science Foundation of China (No. 51407183).