The dyeing effects of scouring and dyeing polyester fabric in one bath were investigated in order to analyze the feasibility of the process.The results indicated that: with scouring and dyeing in one bath,the dyeing effects in the condition of weak acid was better than that in the condition of alkali;compared effects of the new process with that of normal dyeing process,the color fastness to soaping and the fastness to crocking were similar,the value of K/S and the rate of dye-uptake of dyes were a little lower but accepted as well as property of build-up.Among the chosen three disperse dyes,the dyeing performances of Disperse Blue E-R were much closer to normal dyeing process with scouring and dyeing in one bath and in the condition of weak acid;and the process was more feasible for Disperse Blue E-R.