Abstract: A method of solid- phase extraction and ultra performance liquid chromatography coupled with diode array detection was established for the determination of forchlorfenuron in mustard tuber. The sample was extracted with acetonitrile,and cleaned up with solid- phase extraction column.Forchlorfenuron was determined by ultra performance liquid chromatography at 260 nm using acetonitrile- water( 65∶ 35) as mobile phase.The results indicated that the PSA solid- phase extraction column was more effective than others,and the calibration curve showed good linearity when the amount of forchlorfenuron was in the range of 0.1~ 10.0 μg / m L,with correlation coefficient of 0.9993,and detecting limit of forchlorfenuron were 0.03 mg / kg,and the average recoveries ranged from 96.3% to 103.2%,with the relative standard deviation( RSD) of 0.4% ~2.2%. Conclusion: The result demonstrated that the method was simple,accurate and suitable for the identification and quantification of forchlorfenuron in mustard tuber.