Abstract: The pressure of yielding water on the volute keeps constant(the head of work condition for the hydraulic generator) and the generator unit continually changes during the transition when electricity goes off at pump working for the pump-turbine.Based on this regular pattern, the rotation set-up of the runner is changed in the software Fluent.And finally, the purpose of imitating the changes of waterpower in the different work conditions during transition stage for the reversible turbine can be realized.The Reynolds Time Averaged Equation and RNG k-ε turbulence mode are used in the calculation.The implicit(SIMPLEC) method is employed for the coupling of pressure and velocity.The results directly indicate the pressure distribution along the blade surface, flow-field swirl distribution in the volute, and the hydraulic loss at Pump working for the pump-turbine.The results obtained are valuable for runner design and structure optimization of pump-turbines.