The use possibility as a dyestuff of Scutellaria baicalensis was investigated. The optimum conditions were evaluated when silk fabrics were dyed by Scutellaria baicalensis extract. The colorants of Scutellaria baicalensis were extracted better in water than methanol. The optical dyeing concentration was 80%(v/v), dyeing temperature was $80^{circ}C$, dyeing time was 60minites, dyeing repetition was 2 turns. A Post-mordant method showed higher K/S value than premordant one, especially post-Fe appeared the highest value and post-Cr was second. Surface color was all Y. The color fastness was very good at the second repetition of no mordanted silk fabrics, all mordant fabrics were not improved the colorfastness. The antibacterial activity showed at Staphylococcus aureus tested specimen that bacterial reduction rate was 99.7%.