Abstract: To improve the operation stability of distribution networks and meet the demand of high quality power supply,the power supply reliability monitoring technology of active distribution network based on load characteristics is proposed in this paper. The load characteristic acquisition equipment is selected to transmit and collect data by optical fiber network. Combined with the power consumption in different time periods,the load probability model is established to obtain the time sequence characteristics of all the load points in the distribution network. The load point reliability indexes of series and parallel structures are analyzed respectively,and the reliability of distribution system is evaluated by power outage frequency and power outage time. Based on these indicators,we obtain the probability formula of normal operation of distribution network,input basic information in the network,set iteration times and sampling density,and judge whether the power supply meets the power supply demand of all loads during power failure.Simulation results show that the minimum power-off time is 5 hours after the application of the proposed method,which further shortens the power-off time. The power supply reliability values are higher than 0.95,which proves that the monitoring method is significantly helpful to accurately predict power failure.