Abstract: We developed a rapid and accurate method by UPLC-MS/MS to determine the residue of malachite green (MG) ,crystal violet (CV) and their metabolites (LMG and LCV) in aquatic products. Based on the rapid method of SN/T 1768-2006, standard curves were made by adding standard solutions of different concentrations to the blank samples, and D5-MG and D6-LMG were used as internal standards, which improved the accuracy of determination. The results show that MG, CV, LMG and LCV have a good linear correlation within the range of 0~10.0 ngmL-1 (R0.99), and the detection limits of the method are all 0.1 gkg-1. The average recoveries at fortification of 0.5 and 1.0 gkg-1 range from 92.1% to 111.0% with relative standard deviations (RSD) varyingfrom 2.2% to 9.5%. Furthermore, the rapid and accurate improved method is also proved by FAPAS Proficiency Test to meet the export testing requirements of aquatic products.