Dyeing properties of silk fabric with onion shell were studied by investigating the effect of dyeing conditions, such as concentration of onion shell, dyeing temperature, dyeing time and pH, on dye uptakes. And also the effects of mordants and mordanting methods or color change and dye uptakes were investigated. For the practical use, the various color fastness of dyed and mordanted fabric were evaluated. The color fastness was improved when Fe mordant was added.