The natural dyeing of silk fabric with Thuja orientalis extract was investigated. The proper colorant concentration, dyeing temperature, dyeing time, and pH for the dyeing of silk fabric with Thuja orientalis extract were 100% v/v, $80^{circ}C$, 80 minutes and pH 3, respectively. In various mordanted methods, the K/S values of mordanted methods were higher than those of unmordanted methods with increasing mordant concentration. Light colorfastness and washing colorfastness of Cu or Fe mordanted silk fabric was improved by mordanting. The antibacterial properties of dyed and mordanted silk fabric showed a high reduction rate, and Thuja orientalis extract was showed effective bacterial reduction. The dyed and mordanted fabric with Thuja orientalis extract showed a superior ultraviolet protection property.