Abstract: The aim of this study is to use experimental pressure signals to identify whether the airlift pump is operating at its efficiency peak. Pressure measurements were taken at different locations along the riser pipe, collecting data from multiple sensors that cover the characteristics of gas-liquid two-phase flow in various flow pattern. Power spectral density (PSD) and wavelet packet decomposition (WPD) were used to analyze the pressure signals and reveal the relationship between airlift pump efficiency and flow regime changes. The results show that during the slug flow regime, when the sensor located in the middle of the pipe exhibits a peak in the 0-32 Hz frequency range and the singular entropy reaches a valley, it indicates that the gas-liquid interaction is in an optimal state, and the pump's efficiency is at its maximum. Experimental validation confirms that the characteristics of the pressure signal can effectively determine whether the airlift pump is at its efficiency peak under the current gas superficial velocity. This study provides new ideas and methods for monitoring airlift pump efficiency based on pressure signals, offering significant practical value.