Abstract: Rotating stalls are one of the most unstable flow behaviors in centrifugal pumps under low flow conditions. Energy conversion instability, pressure pulsation surge, vibration, and noise intensification often occur in centrifugal pumps under stall conditions, even leading to the fatigue failure of blades in severe cases. The efficient and stable system of centrifugal pumps can then depend on the stall. Alternatively, the gas medium can dominate the performance of the centrifugal pump. Especially, there is the more complex internal flow of the gas-liquid two-phase flow in a centrifugal pump under stall conditions. This study aims to clarify the influence of different inlet gas volume fractions (IGVF) values on the flow characteristics of centrifugal pumps under stall conditions. Euler-Euler inhomogeneous flow and SST turbulence models were also utilized, in terms of external characteristics, internal flow field, gas distribution, and flow monitoring. The performance curve and internal flow characteristics analysis were finally carried out under pure water conditions. The results show that the internal flow field of the impeller appeared alternately stall conditions at 0.70Q_d and 0.65Q_d (Q_d is the design flow rate) in the stall development stage. There was a more serious stall degree at 0.65Q_d. The pump performance decreased under both typical stall conditions, as the IGVF value increased. But there was a smaller decrease in the amplitude, compared with the design and deep stall condition. Furthermore, gas was primarily adhered near the leading edge of the impeller blades on the pressure side. The adhered area gradually increased with the increase of IGVF value. There was also an increase in the relative velocity angle at the leading edge of the stall channel on the pressure side. The flow direction of the liquid phase was close to the suction side as a whole. As such, there was a decrease in the attack angle near the leading edge of the suction side. Furthermore, there was the inhibited fusion of the separation vortex near the leading edge and the vortex in the middle position of the suction side. The stall was finally inhibited. The stall flow field was disrupted when the IGVF value was 2% at 0.70Q_d. But the stall flow field fully disappeared, when the IGVF value was 2% at 0.65Q_d. The circumferential uniformity of the flow field was quantitatively analyzed to introduce the coefficient of variation (CV) of the flow rate between the channels. The CV value of the flow rate between channels decreased gradually, as the flow field improved. Once the CV value was greater than 3.69%, the centrifugal pump was in the stall stage. The stall then disappeared, when the CV value was less than 1.38 %. When the model pump was at the inception point of stall, the CV value was in the range of 1.38%~3.69%. A small amount of gas resulted in a smaller decrease in centrifugal pump performance during stall development, thus inhibiting the occurrence of stall. The circumferential uniformity of the flow field was quantitatively analyzed to clarify the influence of IGVF value on the performance and flow characteristics of centrifugal pumps under stall conditions. The finding can also provide a strong reference to explore the performance balance of gas and centrifugal pumps under stall conditions and the relationship between stall and cavitation, in order to improve the safe and stable operation in the high-efficiency region of centrifugal pumps.