In this paper,liquid chromatography-tandem mass spectrometry was used to determine monascorubramine,monascus red,monascin,ankaflavin of the residues in food,using selected ion monitoring for positive confirmation.Liquid sample is extracted with water by the ultrasonic processor.After centrifugation and volume,solid samples or hemi-solid samples were dissolved to a constant volume by water.Then by C18 solid phase extraction cartridges,eluted sample was determined by LC-MS/MS using external standard method.The detection limits,linear ranges,and recoveries of this method,for monascorubramine,monascus red,monascin,ankaflavin,were 1.0 mg/kg,1.0~100.0 mg/kg and 89.3%~94.3%.This study established a method for determination of monascus pigment in foods.It is quickly and sensitive,and can simultaneously determine many kinds of monascus pigments and their positive confirmations.