This study was conducted to clarify the effects of different natural mordants and mordanting methods on the dyeing degree of silk using extracts from Coreopsis drummondii. Surface colors were shown as an order of descent Y in control, and an order of descent Y and YR treated by mordants. Extracts from Coreopsis drummondii was sufficient for the natural dyestuffs. $10\%,;20\%;and;30\%$ mordants made from lime-juice of Camellia japonica, oyster shells. and Symplocos chinensis (Lour) Druce for. pilosa (Nakai) Ohwi were used for the dyeing of silk. Surface color of silk was not affected by the concentration of mordants and mordanting methods, however, $20\%$ mordant was suitable for the dye coloring. It was shown that dye coloring concentrations were highly in the order of mordanting later > mordanting ahead > co-mordanting, and so on. Silks were naturally dyed by the extracts from Coreopsis drummondii, and twenty-nine kinds of natural mordants were treated and screened. Surface color of silk was shown as an order of descent YR treated by the mordants made from the lime-juice of Camellia japonica and Eurya japonica, and as an order of descent Y by the other mordants. By the treatment of natural mordants, concentrations of dye coloring were significantly increased compared with control (none-mordanting), and the potentials as a natural mordant for the effective dye coloring was sufficiently ascertained.