Abstract: For rational and scientific use of celangulin formulation, the decline dynamics and degradation products of celangulin V in four soils were studied by HPLC-ESI-MS/MS. The decline rates of celangulin V were 68.0% and 65.0% at 90 d in Jiangxi laterite and Shaanxi loess. In Heilongjiang black soil and Tianjin alkaline soil, decline rates were 84.9% and 95.1%, respectively. The degradation products of celanlulin V were also investigated by HPLC-ESI-MS/MS. The result showed that the main degradation products were from the break of varies ester bonds substituted at C-1, C-2 and C-8 of the β-dihydroagrofuran sesquiterpene skeleton.The structures of three metabolite compounds were deduced by their MS/MS spectrum.