The isolated island classification scheme has influence on the optimal load transfer that important on continuous power supply capability. Therefore, it is necessary to evaluate the islanding scheme from the viewpoint of power supply capability. Based on timing characteristics of distributed power (DG) and load, the paper proposes the evaluation index system of power supply capability for distribution network with isolated island operation. According to different operation mode of micro-grid, the evaluation system is divided into distribution network and micro-grid of isolated operation, and selects and designs differentiation indexes. The system includes two new indexes for analysis of the factors influencing the power supply capacity of DG configuration and load characteristic, such as qualified rate of power supply capability, the ratio between the peak load of the power supply and the lowest point of the load. The evaluation for the modified PG E69 node system in different scenes, shows that the index system can evaluate the islanding scheme comprehensively and effectively from the perspective of power supply capability.