Abstract: This paper introduces a study on the variation of characteristic curve of centrifugal pump when pumping gas-liquid mixture, mutual-influence of pressure heads of pump, variation of flow pattern of gas-liquid two-phase and calculation of flow rate as well as shaft power. The viewpoint from authors is that when Qliuid is kept to a constant, with the suction gas-liquid capacity ratio Ksuction within a quite wide variation scope, the shape of characteristic curve of Hmixture is similar to the Ksuction and βmixture as varying with them, and totally related to the second power of Ksuction.