Centrifugal pumps in water conservancy, chemical and other industries are widely used, the choice of its operating point and the analysis of energy consumption is also increasingly valued. The so-called operating point, refers to the actual water pump device in an instant the amount of water, head, shaft power, efficiency and suction on the vacuum height, which indicates that the pump's ability to work. In general, the centrifugal pump flow, head pressure may be inconsistent with the pipeline system, or due to production tasks, process requirements change, the need for pump flow regulation, its essence is to change the centrifugal pump operating point. In addition to engineering design stage centrifugal pump selection is correct or not, the actual use of centrifugal pump operating point selection will also directly affect the user's energy consumption and cost. Therefore, how to reasonably change the centrifugal pump operating point is particularly important. The working principle of the centrifugal pump is to convert the mechanical energy of the motor rotating at high speed into kinetic energy and potential energy of the liquid to be lifted, which is a process of energy transfer and conversion. According to this feature, it can be known that the working point of the centrifugal pump is based on the balance between the energy supply and demand of the pump and the pipe system. As long as the situation of one of the two changes, the operating point of the centrifugal pump will be shifted. Changes in conditions point caused by two aspects: First, changes in piping system characteristics, such as valve throttling; Second, the pump itself changes in the characteristic curve, such as frequency control, cutting impeller, pump in series or in parallel.