Saururus-chinensis was used for the natural due stuff extraction and concentration to produce the condensed dye liquid. Using this liquid, the silk and the cotton fabrics were dyed. And then the K/S value, color difference were measured in order to determine the dye ability and the antimicrobial activity. The K/S values of silk were much higher than those of cotton. In terms of the silk fabric, the Al, Cr-premordanting and Fe, Cu-simmordanting method was most efficient of the mordanting method. The various suface colors on the dyed fabric were resulted according to used mordants and mordanting methods. The dye fastness was significantly improved when mordants were added. Among them, Al-mordant improved more than 1 level. The Cu, Fe-mordants showed the greatest antimicrobial activity on both of mordant treat silk and cotton.