Abstract: The integrated energy system breaks the barriers between different energy sub-systems, and improves the reliability of energy supply and energy efficiency. In project work, it has a relatively long cycle, and it is main for the single-stage planning method. But this method tends to cause low equipment utilization in the early stage and insufficient equipment capacity and poor reliability in the later stage. Aiming at the shortcomings of it, this paper proposed a multi-stage planning method based on generalized multi-energy flow model for integrated energy system. First, the generalized multi-energy flow (MEF) model was established. Then, the multi-stage planning model of the integrated energy system was established with the goal of minimizing the life-cycle cost and the generalized multi-energy flow network equations as the constraint. The equipment or line configuration scheme in each planning stage can be obtained by mixed integer linear programming algorithm. Finally, taking a park-level integrated energy system to be built in North China as an example, a simulation analysis was carried out to verify the effectiveness and economy of the multi-stage planning.