Fault location is one of the key technologies for the development of flexible DC distribution network. The fault location methods of conventional HVDC transmission line are not applicable to the DC distribution network. Considering the DC reactor installed on the line, a fault location method based on DC reactor voltage for DC distribution network is proposed. This method studies the capacitor discharging process of DC fault, and establishes the time domain differential equation based on the DC reactor voltages, which contains two unknown parameters of fault location and transition resistance, and solves the equation by least-squares method. Simulation results by PSCAD show that the proposed method can obtain the fault location and transition resistance accurately, and meet the requirement of DC distribution network fault location. This work is supported by Natural Science Foundation of Xinjiang Uygur Autonomous Region (No. 2016D01C036).