Aiming at the calculation of the total supply capability (TSC) of large-scale renewable energy in the form of distributed generation access to the distribution network, considering the typical output scenarios of new energy and the probability of corresponding scenarios, the model is built with the objective function of maximizing the expected value of load magnification under new energy typical scenarios. The model takes into account the issue of locating the distributed generation and the network reconfiguration, and uses the second-order cone relaxation technique to relax the nonconvex and nonlinear power flow constraints. The model can be transformed into a mixed integer second-order cone programming problem in which the solution space is a convex feasible region and CPLEX is used for effective solution. The 94-bus test system example verifies the correctness of the model. The simulation results show that the total supply capability of the distribution network can be improved by taking into account the distributed generation’s access, and the capacity, location and access mode of the distributed generation have a certain influence on the total supply capability of the network.