The technology of processing sweet potato flour using a drum dryer was studied. Effect of the material temperature, material thickness, roller rotating speed, and roller temperature on the technology in which flour color and the cumulate density were taken as response values was analyzed with response surface methodology. For design of process requirement, optimum conditions were as follows: material temperature was 42℃, material thickness was 13.6%, roller rotating speed was 3.0r/min, and roller temperature was 143℃. Under such conditions, the cumulate density was 0.51g/mL, which coincided with actual values within the 95% confidence interval. Predictive models are feasible in practice.