Abstract: The water conveyance and power generation system network of cascade hydropower station, which has many types of pipes and joints, is complicated. Traditional calculation programs for the transition process of hydropower station can’t model, determine the topological relationship of pipeline network and calculate it. Aiming at the layout of water transmission and power generation system of series hydropower stations, this paper develops a set of visualization software for modeling and calculation of transition process of multistage series hydropower station based on Qt library. According to the functional requirements of the software and the design idea that each module is independent, the software is divided into three modules: drawing module based on Qt graphics view framework, calculation module based on transient flow and post-processing module for results processing. The three modules are connected with each other, and users manage the three modules through the main interface. Finally, the practicability and correctness of the software are verified by engineering examples.