Abstract: This paper summarizes the existing research on the numerical simulations of the disc pump, and found that the existing studies usually set the water body in the connecting column area and the water body in the impeller as a whole as a stationary domain, while the actual situation is that the water body in the connecting column area rotates with the rotation of the impeller, and there is no study to assess the impact of this simplified treatment. In this paper, two different modeling scenarios are developed for this region: one is consistent with the existing studies and sets the water column in this region as a static domain (Scheme I), and the other sets the region as a rotating domain (Scheme II) according to the actual situation. Numerical simulation of the flow in the disc pump was carried out using the Realizable k-ε turbulence model based on the Fluent platform. The velocity distribution, total pressure distribution, turbulent kinetic energy, streamline distribution, pump head and efficiency of the disc pump are analyzed under different flow conditions (0.8Qn, 1.0Qn, and 1.2Qn), and the pump performance test rig is constructed to validate the calculation results. By comparing the numerical results of the two schemes, it has been found that a significant low velocity region on both sides of the connecting column in scheme I, whereas the local velocity value is higher for scheme II due to the set-up of near wall fluid. Because of the vortexes generated by flow separation from the blade surface, local low-pressure areas are presented on the blade suction side for two schemes, and the formed vortexes also result in the increase of local energy dissipation. Therefore, the turbulent energy dissipations in the disc pump are mainly concentrated in the blade suction side, whereas the energy dissipations near the pump inlet and outlet are small. After the fluid flows through the connecting column, the circumferential velocity and the circumferential component of the absolute velocity of Scheme II are smaller than the values of Scheme I, which indicates that in the actual operation of the disc pump, the losses generated by the blocking effect of the connecting column on the outlet flow is greater than the energy brought by itself, resulting in the head of Scheme II lower than Scheme I. The calculation results of the two schemes are consistent with the trend of the experimental results, and the performance differences between them are rather small, which means schemes I is simpler and efficient if only consider the rapid calculation of pump performance. However, scheme II is preferred if the aim is to get more comprehensive and accurate internal flow information.