Abstract: OBJECTIVE To investigate and compare the effect of tetramethylpyrazine(TMP), epigallocatechingallate (EGCG), extracts of gingko and ginsenoside Rg1 on different dosages of ultraviolet B(UVB)-induced biological behavior of primary human melanocytes. METHODS Primary melanocytes were separated and developed, cells were irradiated with different dosages of UVB(30, 90 mJ·cm^-2 respectively), and then incubated with different concentrations of four plant drug monomers or extracts(TMP 100, 300, 600 μg·mL^-1; EGCG 10, 20, 40 μg·mL^-1; extracts of gingko 40, 80, 160 μg·mL^-1; ginsenoside Rg1 50, 100, 200 μmol·L^-1) for 72 h. Cell proliferation was determined by MTT assay, tyrosinase activity was determined by DOPA oxidization reaction assay and melanin synthesis was determined by NaOH assay. RESULTS The 30 mJ·cm^-2 UVB promoted the proliferation of melanocytes, tyrosinase activities and melanin synthesis, while TMP, EGCG and extracts of gingko inhibited these effects in various degree, and the effect of EGCG was the most obvious; 90 mJ·cm^-2 UVB showed toxicity to melanocytes, as the cell proliferation, melanin synthesis, were all declined, and TMP, EGCG, extracts of gingko and ginsenoside Rg1 especially TMP could retrieve this effect distinctly. CONCLUSION TMP, EGCG and extracts of gingko can not only inhibit the proliferation of melanocytes and melanin synthesis induced by low-dosage of UVB irradiation, but also retrieve the toxic effect of melanocytes induced by high-dosage UVB irradiation and have a certain photoprotective effect on melanocytes.