Six popular plants used in skin disease(dermatosis) are selected to test the influence of their extracts to the activity of tyrosinase. The results show that Stellaria media (L.) Cyr., Stenoloma chusana (L.) Ching, Sedum sarmentosum Bunge and Humulus scandens (Lour.) Merr. have inhibitory effects. Bidens bipinnata L. and Pueraria lobata (Willd.) Ohwi have no obvious inhibitory or stimulative effects.