Abstract: Electric submersible pumps (ESPs) are widely used in oil and gas extraction processes. It is of great significance to study the gas-liquid two-phase flow characteristics for improving pump energy efficiency, extending equipment life, and reducing failure rates. This paper summarized the evolution of the gas phase within the pump and analyzed the variations in gas-liquid two-phase flow under different flow regimes. It also reviewed the mechanisms of gas-liquid two-phase flow, focusing on the development of empirical correlations for two-phase flow models, the application of visualization experiments, and numerical simulation methods in the study of flow mechanisms. Addressing the issue of low gas-liquid mixed transport performance, this paper outlined the current state of research on gas-liquid mixed transport optimization design and proposed optimization strategies tailored to the characteristics of ESPs. Finally, the paper looked forward to future research directions in the field of gas-liquid mixed transport in ESPs.