Abstract: This study systematically investigated the impact of volatile components in white pepper essential oil extracted via ultrasound-assisted steam distillation, utilizing molecular sensory science. Two extraction methods were systematically compared: conventional hydrodistillation and ultrasound-assisted hydrodistillation. Then, the volatile components in these two white pepper essential oils were analyzed using liquid-liquid extraction (LLE) in conjunction with comprehensive two-dimensional gas chromatography-olfactometry-time of flight mass spectrometry (GC×GC-O-TOF-MS). Additionally, aroma extraction dilution analysis (AEDA) was conducted to screen for aroma-active compounds with a dilution factor (FD) of ≥32 for precise quantification, and their odor activity values (OAVs) were subsequently calculated. The results indicated that a total of 111 volatile odor compounds, including 49 terpenoids, 27 alcohols, 12 ketones, 8 aldehydes, 5 esters, and 10 other compounds, were identified in the two white pepper essential oils. By comparing the types and concentrations of volatile compounds in these oils, it was observed that ultrasound-assisted hydrodistillation exhibited effective extraction of terpenoids. Olfactory analysis detected odors from 41 aroma-active compounds in the two white pepper essential oils. The OAV values of aroma-active compounds, including 3-carene, myrcene, α-terpinene, (+)-limonene, p-cymene, caryophyllene, linalool, and terpinine-4-ol, in white pepper essential oils obtained through ultrasound-assisted hydrodistillation were all increased. These findings suggested that ultrasound-assisted hydrodistillation not only improves the extraction rate of white pepper essential oil but also effectively promotes the generation or release of aroma-active compounds. This study provides a methodology and insights for enhancing the flavor quality of plant essential oils extracted by traditional hydrodistillation.