OBJECTIVE To study the components of ethyl acetate fraction in Qubai tablet ，and its pharmacodynamics on de melanocyte model ，and explore the material basis for anti-vitiligo effect of Qubai tablet. METHODS The ethyl acetate fraction of Qubai tablets was obtained by extraction ，and its components were analyzed by ultra performance liquid chromatography-mass spectrometry（UPLC-MS）. Model control group ，vehicle control group and 8-methoxypsoralen（8-MOP）administration groups （10，50，100，150，200 μmol/L），ethyl acetate fraction administration groups of Qubai tablet （10，50，100，150，200 μg/mL） were set up in the experiment. By establishing the de melanocyte model ，the effects of ethyl acetate fraction of Qubai tablet on de melanocyte were studied from four aspects ：cell number ，cell viability ，melanin formation and tyrosinase activity. RESULTS UPLC-MS component analysis preliminarily determined the structure of 64 compounds in the ethyl acetate fraction of Qubai tablet ， of which 14 compounds were detected in positive and negative ion mode ；psoralen compounds accounted for the largest proportion ， and the content of psoralen chromone chalcone was the highest in positive and negative ion mode. The results of pharmacodynamic study showed that the ethyl acetate fraction of Qubai tablet could increase the number of de melanocytes ，and significantly improve the cell proliferation rate ，the rate of promoting melanin formation and the rate of promoting tyrosinase activity in the process of melanin formation （P＜0.01）. CONCLUSIONS Psoralen compounds may be the material basis for the anti-vitiligo effect of ethyl acetate fraction of Qubai tablet ；good anti-vitiligo effect of ethyl acetate fraction of Qubai tablet may be related to the promotion of tyrosinase activity.