A multi-heat source ring-shaped heat-supply network is not a plane net and supply-return pipe net is dissymmetric under faulty condition. We present a method for topology structure of spatial heat-supply network based on graph theory. With object-oriented programming,it defines graph and includes correlation arithmetic according to basic structure information of supply-return pipe net and builds incidence matrix and fundamental circuit matrix automatically. It creates a spatial heat-supply network "tree"which includes information of heat source and heat users and adopts breadth-first search based on plane graph. According the tree,basic incidence matrix and fundamental circuit matrix of spatial heat-supply network are established. In simulating heating network of Harbin development zone,a program of multi-heat source ring-shaped heat-supply network in topology structure is build and computing performance is verified. It provides a method for complex heat-supply network hydrodynamic condition analysis and dissymmetric heatsupply network calculation based on arithmetic of graph and adapts to various model pipe nets.