Abstract: With the widely application of distributed generation(DG) and its increasing influence on power supply capability of distribution network, current calculation model of power supply capability for distribution network still does not consider the load transfer capability of DG that connected to low-voltage bus of substation. In order to analyze impacts of the load transfer capability of DG on total supply capability (TSC) for distribution network, the TSC analysis model for distribution network is proposed firstly by considering the load transfer capability of DG according to DGs types and characteristics. To solve the optimization problems in the model, the analytical method based on interconnection characteristics of distribution system is applied. Then topology simplification thought is put forward based on interconnections among feeders. Finally, the correctness of the model and algorithm is verified, and the results are checked and analyzed through the numerical example of a concrete distribution network. Simulation results show that the DG connected to distribution network can promote the regional TSC and strengthen the distribution system capability to prevent the N-1 fault.