This study was conducted to evaluate the quality characteristics and antioxidant activities of rice flour sponge cakes containing 0, 20, 30, 40, and 50% Helianthus tuberosus powder (HTP). As HTP content of sponge cake increased, the pH of sponge cake batter significantly decreased, whereas specific gravity significantly increased (p<0.05). Meanwhile, volume and symmetry indices of sponge cake were inversely proportional to HTP amount. Further, with higher HTP content in sponge cake, L and b values of crumbs significantly decreased (p<0.05), whereas a value significantly increased (p<0.05). L, a, and b values of crust significantly increased with higher HTP content. For texture characteristics, hardness, cohesiveness, gumminess, and chewiness of sponge cake significantly increased (p<0.05),whereas cohesiveness did not significantly change. In the sensory evaluation test, rice sponge cake prepared with 10% HTP showed the highest sensory scores in terms of color, flavor, taste, softness properties, and overall preference. The levels of total polyphenol compounds and DPPH radical scavenging activities of rice sponge cakes significantly increased with higher HTP contents (p<0.05). The results of this study suggest that rice sponge cake containing 10% HTP is the most appropriate for quality characteristics and sensory evaluation. This study also provides a way to increase the quality, texture characteristics, and organoleptic properties of sponge cake while reducing HTP content to less than 10% in order to satisfy consumer tastes.