Teed lines are widely used in rural power networks in China. The paper theoretically analyzes the voltages and currents when a single line-to- ground fault occurs, constructs a new mathematical model for fault location on the teed lines, performs corresponding MATLAB simulations. Simulation results show that currents near the source (bus M) are almost independent of fault positions and fault resistances. However, voltages at bus M are sensitive to fault positions while fault voltages at fault position are only sensitive to transient resistances. A novel approach to fault location on teed lines is proposed. First, the faulted line is identified with remote control equipment. Then, the transient resistances are calculated according to the fault voltages. And at last, the fault distances are computed according to the voltages at bus M and the calculated transient resistances.