<p>This study systematically investigated the effect of hydrodistillation (HD) on the yield of essential oil derived from <i>Cyperi Rhizoma</i> following ultrasonic pretreatment using natural deep eutectic solvents (NADES_S) as the medium. The parameters for ultrasonic pretreatment were analyzed using single-factor experiments and response surface methodology (RSM) to optimize the yield of essential oil. The findings indicated that the ideal settings for ultrasonic pretreatment were as follows: The water content of NADES-5, with a molar ratio of lactic acid to choline chloride of 3.25:1, was 38.6%. The ultrasonic treatment duration was 42.0&#xa0;min, the ultrasonic power was 73.0&#xa0;W, and the actual essential oil yield attained 1.341%. Scanning electron microscopy (SEM) analysis revealed that the application of NADES-5 as the extraction medium resulted in considerable degradation of the powder’s composition, as evidenced by the presence of numerous tiny pores on the surface. This suggested that NADES-5 enhanced permeability and exerted an erosive impact, efficiently dismantling the plant cell wall. Gas chromatography-mass spectrometry (GC-MS) analysis identified 33 distinct components in the essential oil extracted via HD following ultrasonic pretreatment using NADES-5 as the solvent. This study illustrated that employing NADESs as the medium for ultrasonic pretreatment markedly improved the yield of essential oil derived from <i>Cyperi Rhizoma</i>, presenting a novel approach for effective essential oil extraction.</p>