An ultra performance liquid chromatography-tandem mass spectrometric（UPLC/TUV-MS/MS） method was developed for the determination and validation of laccaic acids in juice.The juice samples were cleaned by solid-phase extraction technique with Oasis? HLB cartridge.The targeted compounds were separated on a Waters Acquity UPLC BEH Shield RP C18 column with acetontrile-0.1% formic acid as mobile phase by gradient elution,and detected with TUV detector at 286 nm.A quadrupole mass spectrometer with atmospheric electrospray ionization source was used for the identification under SIR mode and the collision induced dissociation analysis.The external standard method was used for quantitation analysis.It was found that the lac dye extract consisted of laccaic A,laccaic B,laccaic C and laccaic E,of which the relative contents were 57.95%,31.33%,6.12% and 2.96%,respectively,based on the area normalization method,and the calibration curves for four laccaic acids showed good linearities in the range of 0.029-11 mg/L with correlation coefficients higher than 0.999.The average recoveries of high,medium and low three spiked concentration levels were between 83% and 111%,with relative standard deviations（RSDs） of 2.3%-9.2%.The limits of detection（LOD） were in the range of 0.008 7-0.17 mg/kg for the four components in juice matrix,and their limits of quantitation(LOQ) were 0.029-0.58 mg/kg.The results demonstrated that the proposed method for laccaic acids determination in juice could meet the requirements for the natural color analysis in food safety.