Abstract: A method of HPLC-MS/MS for the determination of nonylphenol in cosmetics was proposed. The sample was extracted ultrasonically with mixture of CH3OH-CH2Cl2(8+2) for 30 min except using mixture of C2H5OH-CH2Cl2(8+2) for lipstick. After centrifugation, the supernatant was taken for purification on Oasis HLB solid phase extraction column. The nonylphenol in the eluate from the SPE column was separated on Waters XBridge C18 column (2.1 mm×150 mm, 3.5 μm) by gradient elution with mixtures of CH3OH and ammonia (0.1+99.9) solution in different ratios, and determined by MS/MS. The negative electrospray ionization as well as multiple reactions monitoring mode was used in the detection. The internal standard method was used for quantification of nonylphenol. Linearity range of nonylphenol was kept from 10 to 500 μg·L-1, with lower limit of determination (10S/N) of 0.2 mg·kg-1. The proposed method was applied to the analysis of 4 kinds of cosmetic samples, giving values of recovery in the range of 83.1%-103.0% and RSD′s (n=6) in the range of 2.75%-9.24%.