In order to study the pump internal flow characteristics when the electric submersible pump was used to transport gasliquid twophase flow under variable frequency and variable speed operation, the transient simulation of gasliquid twophase flow in the impeller of the electric submersible pump was carried out based on the Eulerian-Eulerian nonuniform flow model, the unsteady Reynolds time averaged N-S equation and the standard κ-ε turbulence model, taking the impeller of the Q10 electric submersible pump as the research object. The results show that the gas phase is not evenly distributed in the flow channel as the impeller rotates, and the gas phase is mainly concentrated in the flow channel near the inlet side of the front cover plate, the gas phase exhibits periodic aggregation and diffusion in the flow passage; when the rotating speed of the impeller increases, the period of periodic gas phase aggregation and diffusion in the flow passage is shortened, and the concentration of gas phase in the impeller decreases, the overall flow velocity in the flow passage increases, and the pressure difference between inlet and outlet increases; the impeller speed increases, the pressure difference between the two sides of the blade increases, and the fluctuation frequency of the blade surface load increases.