There are many types of components in the distribution network, and the reliability tracking method is one of the main methods to identify the weak points of the distribution system. Traditional reliability tracking methods is based on failure mode and effects analysis, which is hard for analyzing large scale distribution network. To fill this gap, this paper proposes a Monte-Carlo-based method for identifying weak points of the distribution networks. Firstly, the Monte Carlo method is used to calculate the reliability index of distribution networks with considering the topology and component parameters of distribution network. Then, the reliability tracking analysis is used to obtain the influence factor of each component on the system reliability index and the weak point of the system is determined by the size of the influence factor. Finally, a typical low-voltage power distribution system with 10 load nodes is analyzed, the weak links of the system are identified and the reliability improvement measures are given. The effectiveness of the proposed method is verified by comparing the improvement of system reliability index before and after the modification of weak point.