With the development of the distribution network, the large number of T-connected branches complicates the network structure. Traditional ranging algorithms often overlook the branches, resulting in decreased ranging accuracy. Researching the precise location of single-phase ground faults in distribution networks with multiple branches is therefore significant. To address this, an accurate single-phase ground fault ranging method based on back-and-forth segment- by-segment approximation for distribution networks with multiple branches is proposed. First, the distributed parameter model is analyzed. From the relationship between zero sequence voltage and current, a discriminant coefficient of fault section is proposed to determine the minimum fault section. Secondly, the fault location function is established by using the zero sequence voltage and current at both ends of the minimum fault section, and the gradient descent method is used to solve the accurate fault point. Finally, the proposed method is validated on the PSCAD simulation platform. The results demonstrate that the proposed method can identify the minimum fault section, accurately calculate the fault point, and exhibits strong resistance to transition resistance, making it well-suited for accommodating high-permeability distributed generation.