Fault location technology in distribution network is the key technology to ensure the safe and reliable operation of distribution system. In order to determine the location of fault in time and effectively, a fast method of time domain fault location for single phase to ground fault in distribution network is studied in this paper. Firstly, the equivalent model of single phase to ground fault of distribution line is established, and the relation between fault point and fault information of bus side and load side is analyzed, and time domain distance measurement equation is established. Then, through the analysis of the line parameters at a specific time, the calculation process is simplified and the fast fault location is realized. Finally, the proposed method is simulated by Matlab, and the feasibility and effectiveness of the proposed method are verified. Experiments show that this method is of short time, has high precision, and is not affected by fault resistance. It provides a new idea for single phase to ground fault location in distribution network. This work is supported by National Natural Science Foundation of China (No. 61672032).