Study the chemical constituents and their tyrosinase inhibitory activity in the leaves of Castanopsis ceratacantha.The compounds were isolated and purified by Sephadex LH-20,Toyopearl HW-40F,Diaion HP20SS and other column chromatography and HPLC.The structures of compounds were elucidated by spectroscopic data and comparison with literatures.The characteristic compounds in the leaves of C. ceratacantha were screened for tyrosinase inhibitory activity.In the previous research,our group had isolated 11 compounds from the 80% ethanol extract of C. ceratacantha. On the basis of this research,17 compounds were obtained and their structures were identified as protocatechuic acid (1),6-O-galloylarbutin (2),3-methoxy-4-hydroxyphenol 1-O-β-D-(6′-O-galloyl) glucopyranoside (3),valoneic acid dilactone (4),1,2,3,4,6-penta-O-galloyl-β-D-glucopyranose (5),pedunculagin (6),casuarictin (7),praecoxin A (8),castalin (9),vescalin (10),chinquapinic acid (11),vescalagin (12),castalagin (13),castacrenin D (14),kaempferol (15),isoquercitrin (16),aviculin (17).All the compounds were isolated from this plant for the first time.Experimental results show that compound 14 has strong tyrosinase inhibitory activity,and other compounds also have better inhibitory activity.