27% ImidaelopridoThiramoCarbendazim FS for cotton seed treatment was analyzed by HPLC.They were separated and determined by using a 150×4.6 mm stainless steel column packed with Hypersil ODS C18,with methanol-acetonitrile-water as the mobile phase and UV detection at 272nm.The method was rapid and accurate.RSD of Imidacloprid,Thiram and Carbendazim were 0.0724%,0.0443% and 0.0539%,linear correlation coefficients were 0.9999,recovery ratios were 101.59%,94.61% and 99.11%.