Based on the RNG k-ε turbulent model and Reynolds Navier-Stokes equation, the hydraulic performance of the bidirectional shaft tubular pump was simulated with the commercial CFD software. By comparing the hydraulic loss of each part, the results indicated that the hydraulic loss at the tail of the shaft tubular was large when the shaft tubular was used as inlet passage, and the hydraulic loss near the outlet of the vane and the bifurcation of the shaft tubular was also large when the shaft tubular was used as outlet passage. The hydraulic losses of the shaft tubular and straight passage were small when they were used as inlet passages due to the frictional head loss, but the hydraulic losses were large when they were used as outlet passages, with the effect of circulation and spread section, the flow was easy to be taken off, thus the hydraulic losses were large. The performance of the pump unit was improved compared with the original case, as the head loss was significantly reduced by adjusting the hull lines of the flow channel, and finally the hydraulic performance optimization design was finished. The efficiency of the simulation was up to 72.0% under positive condition, and it was up to 57.9% under reverse condition, the efficiency of the model test was up to 70.4% under positive condition, and it was up to 56.2% under reverse condition.