Abstract: To explore the formation of off-flavour compounds, the ?avour components of white pepper were analyzed at different processing steps. Using the fresh pepper fruit as raw material, the static and exchanging water soaking methods were used for processing white pepper. The flavour compounds were extracted by headspace solid phase micro-extraction and steam distillation, and identified by gas chromatography-mass spectrometry (GC-MS). The flavour composition and differences were analyzed for the samples of soaking 3 days, 6 days and the final products. The results showed that 167 compounds were detected in white pepper corn and the content of β-caryophyllene was the highest, ranging from 20.64% to 28.31% of relative content. Secondly, limonene content was between 6.89% and 11.24%.The off-flavour compound (3-methyl indole) was detected in white pepper prepared by soaking in static water. A total of 31 compounds were detected in white pepper essential oil, in which terpenoids such as 3-carene (21.94%-24.64%), β-caryophyllene (17.51%-22.21%), limonene (18.04%-19.26%), β-pinene (9.63%-10.67%) were the major flavour components of white pepper. The off-flavour could be detected in static water soaking for 3 days, but the off-flavour were not found in the white pepper prepared from exchanging water.