The S-shaped region of complete characteristics on pump-turbine is caused by centrifugal force larger than common hydraulic turbine. The flow on that S-shaped region is very much unsteady. In order to obtain the flow on that region, the steady and unsteady simulations were analyzed on turbine, turbine runaway, turbine brake near no-discharge, anti-pump near no-discharge and anti-pump operation conditions which run on S-shaped curve. The results showed that much large eddy existed in vanes and runner. That eddy wasted much water energy and reduced turbine output. Through the unsteady simulation of S-shaped curve, it is found that the pressure pulsation frequency and amplitude in spiral casing and cone of draft tube are similar and the amplitude is small. The pressure pulsation amplitude on guide vanes and blade inlet are high, and those frequencies are also high. Those simulations are always used to know the essence of S-shaped region and reduce the unsteady characteristics. 