Abstract: Pointing to the starting phenomenon of axial flow pump when the outlet water level is higher than the bottom elevation of the hump,this paper selects three influencing factors such as gate opening time,gate pre-opening and super hump height to establish an orthogonal test scheme,and the starting characteristics of pumps are studied in combination with transient flow theory. The research shows that under the super hump condition,the pump head first quickly increases to the maximum,and then gradually decreases to the stable value;the pumping flow starts a back flow,then quickly changes to positive within 3s,and gradually reaches the stable value. The maximum starting head is mainly affected by the hydraulic loss at the gate,so the gate pre-opening has the greatest impact,the gate opening time has the least impact.The maximum backflow flow is also most affected by gate pre-opening,and the other have little influence and the same weight. At last,“the gate opened in 240 s and pre-opened by 30%”determines the optimal starting scheme of the pump.