As the network is becoming complicated and two-way interactive, it’s necessary to analyze every user’s power supply reliability based on the operating of the network. The essay evaluated the power supply reliability of different nodes in the distributed network with distributed generation from the perspective of the users’ power outage consequence, according to the equivalent load tree model of distributed network, combining load nodes’ loss of electricity and the value of electricity loss, the concept and computational model of load nodes’ equivalent loss of the electricity quantity was proposed. Combining the concept model of equivalent loss for load nodes’ electricity and the power outage duration index of the reliability of distribution network, the evaluation method of the power supply reliability calculation of Monte Carlo considering the equivalent loss index of the electric quantity was proposed. The efficiency for the method is proved by the example, and the method also provides suggestions for network specific rebuilding and the selection of operation mode of distribution network.