Abstract: Chloramphenicol residues in milk were detected by UPLC-MS/MS.The protein in milk was first precipitated by perchloric acid,and chloramphenicol in milk was extracted by homogenization with ethyl acetate.After purification,the chloramphenicol was separated by high performance liquid chromatography with C18 column as stationary phase and acetonitrile-water as mobile phase.The chloramphenicol residues were detected by MS/MS in the ESI（-）-MRM mode.This method can avoid the false positive results of routine HPLC,largely reduces separation time,and improves sensitivity.It can be used detect chloramphenicol in milk,and the detection is satisfactory.