This study investigated the quality characteristics of gruel supplemented with purple sweet potato. The gruel was prepared with rice powder, salt, and various amounts of purple sweet potato (0, 2, 4, 6, 8%). Increasing the content of purple sweet potato decreased the pH and viscosity of the gruel, whereas sugar content and spreadability gradually increased. In addition, the content of purple sweet potato increased, the lightness (L) significantly decreased, while redness (a) and yellowness (b) increased. The results of the sensory evaluation show that overall-acceptability was highest for the gruel containing 6% purple sweet potato. In conclusion, the results shows that the gruel with 6% purple sweet potato is the best. This study indicates that it is possible to enhance the quality and acceptability of gruel by adding purple sweet potato powder.