Abstract: A method for determination of the residue and degradation dynamics of paclobutrazol in rapeseed plant,rapeseed and soil was described.Samples were extracted with dichloromethane and the extracts were purified on Si-Mg absorbent column,followed by determination using GC.The recovery was from 88.10% to 110.2% for the rapeseed plant,93.4% ~108.8% for soil and 83.5% ~108.7% for the rapeseed with coefficients of variation of 1.09% ~5.27%,1.47% ~3.36% and 0.98% ~5.13%, respectively.The minimum detectable limits of the method was 1.0×10-11 g.The minimum detectable concentration was 0.01 mg/kg for soil,0.05 mg/kg for rapeseed plant and rapeseed.The degradation half-life of paclobutrazol was 4.80 ~7.12 days in rapeseed plant and 12.31 ~17.11 days in soil.It was found that paclobutrazol degradates faster in rapeseed plant than in soil.