The gray wolf algorithm (grey wolf optimizer, GWO) is easy to fall into the trap of local optimum when it is used for fault location in distribution network with a large number of nodes. The performance of gray wolf algorithm is improved by introducing longicorn whisker algorithm and improving gray wolf algorithm (beetle grey wolf optimizer, BGWO), and a 33-node distribution network is taken as a simulation example to verify the effectiveness of the algorithm. The results show that the algorithm has high reliability and high fault tolerance when locating the fault section in the distribution network with distributed generation.