The work aims to intensively study the technical performance of sine pump and carry out dynamic modeling and simulation calculation on its impeller rotor. Equivalent mechanical model of the rotor was established based on structural design and theoretical analysis, and its finite element modeling program was developed with elements BEAM188, MASS21 and COMBI214. On the basis of modal parameter calculation and rotor dynamic analysis with multi-load step, the critical speeds of the rotor from the 1st order to the 3rd order based on Campbell chart were determined. A simulation model of rigid multibody dynamics was set up by ADAMS/View software. The pressure field in the pump was simplified into an equivalent moment on the spindle, and the dynamic simulation and analysis of the rotor assembly were carried out with the contact characteristics taken into consideration. The actual working speed (600-800 r/min) of the rotor was far less than its first-order critical speed (29 824.36 r/min). Besides, there was a large contact force between impeller and scraper, and the dynamic impact load on support bearing was larger than others. With good rotor dynamic characteristics, the impeller assembly can adapt to the structural principle and actual working conditions of the sine pump.