The dyeability of the Eucommiae Cortex were examined to establish the optimum condition for dyeing of Eucommiae Cortex. The results of this study are as follows, Wool, nylon and silk had the highest K/S value at pH 3. The dyeability was the highest in wool, nylon, and silk. In addition, the increase in K/S value corresponded to temperature in wool, nylon and silk, and the greatest K/S value at 95$^{circ}C$. The increase in K/S value corresponded to dyeing times in wool, nylon and silk, and the greatest K/S value at 120min. Also, the K/S value increased in concomitance with the increased number of dyeing repetition. In the most cases, colorfastness of light was low but colorfastness of laundry, sweat was relatively good.