With more and more Distributed Generation (DG) access to distribution network, islanding operation has become an important operation mode. Therefore, it is significant to partition island reasonably. Firstly, on the basis of the characteristics of distribution networks, the average level and the average degree as the objective functions are proposed. Secondly, according to multi-objective problem of island partition, the determination method of branch and node priority level is proposed. On this basis, an algorithm on island partition of the distribution system based on heuristic rule is proposed. The DG node (or the island formed by the DG node) is as the root, and guideline of “search and modulation” is used for solving method. Finally, the effectiveness and rationality of this algorithm are validated by simulation case, which takes connective switch, load importance, controllability of load, node level, node degree and load capacity into account. This work is supported by National Key Research and Development Program of China (No. 2017YFB0902000).