Swing-type device and generating system is a new type of energy converting system. It converts water flow energy into electricity by the blade's swinging in the flowing water. The device is composed of supporting system， blade， blade motion organ， collision and return organ， transition system and electricity generating system. The hydrodynamic model of blade is established based on the stream tube method. The dynamic model of system is established according to the institutional characteristics of the system. The dynamic characteristics of the system are analyzed by simultaneously solving the coupled hydrodynamic model and kinetic equations. The comparison between numerical results and experimental results proves the effectiveness of the model. The research results are of importance to the design of swing-type flow energy generation system.