Abstract: During the production of ultra-deep gas wells, a retained oscillating liquid column may form in the wellbore, leading to inaccurate predictions of liquid loading. This phenomenon is referred to as dynamic liquid loading. To investigate the identification and formation mechanism of this phenomenon, laboratory experiments for visualizing physical simulation of gas-liquid two-phase flow were conducted, as well as research on the transient simulation of OLGA multiphase flow. The phenomenon that a liquid column within the wellbore could move up and down without causing the gas well to shut down was reproduced, indicating that the essence of the dynamic liquid loading phenomenon is that a liquid column moves up and down repeatedly within the wellbore. Under certain gas-liquid ratios and well depths, the gas well can operate stably at a flow rate lower than the critical liquid loading flow rate. Experimental results show that when the in-situ gas-liquid ratio falls below 50 m³/m³, the liquid loading capacity is greatly reduced, while higher ratios within a certain range intensify the dynamic liquid loading phenomenon. Extrapolation using the Euler similarity criterion identifies the maximum and minimum gas-liquid ratios and the critical well depth. The dynamic liquid loading phenomenon reveals the conditions under which ultra-deep gas wells can maintain stable production at a flow rate lower than the critical liquid loading flow rate. It provides a basis for determining the appropriate timing of artificial lift intervention, optimizing drainage gas recovery parameters, and enhancing production efficiency.