Due to the human carcinogenic effect of musk ketone it is the restriction ingredient in cosmetics, and the content analysis of musk ketone is necessary. The various matrixes of cosmetics are prepared by using ultrasonic-assisted extraction. A reversed-phase high performance liquid chromatography method for the determination of musk ketone in cosmetics is established. The samples are analyzed under the condition of Kromasil-C₁₈ column (250mm×4.6mm i.d., 5μm) with UV 235nm. The mobile phase is a gradient elution with V(CH₃CN):V(H₂O) = 80:20 at a flow rate of 1.0mL/min. Results show that as the concentration of musk ketone is in the range of 0.5-150μg/mL, the relationship between concentration and the corresponding peak area presents the good linearity (r=0.9998). The regression equations could be expressed as A=13500ρ-4829; and the recovery ratio of musk ketone achieves at 90.5%-102.5%. The RSD of the method is 0.45%-0.98%. Therefore, an accurate and stabilizing method with extensive applications is proposed and built. The method provides the reference for the analysis on musk ketone and for the establishment of the state regulations.