Abstract: Based on a modle of heating three spaces by hot water and electricity, the corresponding energy network was established, and the energy network equations were established according the generalized Kirchhoff's laws. The working condition of all branches can be obtained by solving these equations. For each additional heating space, the energy network equation increases four variables (two intensive variables and two extensive variables). Two extensive equations and two constraints provided by the heat load are also added at the same time, the equations are closed and solvable, which indicates that the equations can be extended to the energy network with any number of heat load. A set of typical data is used to calculate the working status of each equipment in three heat load energy networks. The results are the same as those calculated by electric network and fluid network respectively. It shows that the established energy network equation and its solution method are reliable. This study can provide theoretical guidance for the analysis and optimization of integrated energy system.