With the continuous expansion of the distribution network and the access of distributed generation, the problem of distribution networks with distributed generation (DG) fault location has become complex and difficult to solve. In order to locate faults accurately and quickly, in this paper, the quantum ant algorithm is applied to solve this problem for the first time. Firstly, we establish a reasonable mathematical model. To greatly avoid the adverse effects of information loss, we propose an information self-correction method. Secondly, a hierarchical positioning model is proposed to shorten the positioning time. Then considering the requirements of quickness and accuracy for fault location, the algorithm is improved. We update the quantum rotation gate mechanism and dynamically adjust the rotation angle. In addition, we add the mutation mechanism to expand the population diversity. Finally, the effectiveness and performance of the improved quantum ant colony algorithm are reflected by comparing with other algorithms. Simulation results demonstrate that the improved quantum ant colony algorithm has substantial global optimization ability, high fault location accuracy and fault tolerance in different cases, and the hierarchical positioning model can shorten the algorithm location time.