In order to improve the reliability of power supply in distribution network, an optimal placement method of fault indicators based on integer linear programming model is proposed. Based on the small current grounding operation mode of distribution network, this paper establishes a mathematical model for the patrol time of any fault points on multi-branch power lines, aiming at minimizing the investment and maintenance cost of fault indicators, thereby reducing the outage time of distribution network. By reasonably configuring the location of the fault indicator on the distribution line, this paper ensures that the precise location time of any fault point does not exceed the allowable operation time of the system with fault, and maximizes the reliability of power supply for users. Finally, a practical 10 kV distribution system in Jiangsu Province is analyzed by an example. The test results show that the proposed model can accurately locate different fault points within the allowable operating time of the system with fault and effectively reduce the investment and maintenance cost of the fault indicator. This work is supported by National Key Research and Development Program of China (No. 2018YFB0904500) and the Science and Technology Project of Jiangsu Electric Power Company (No. J2017143-2).