This study investigated the quality and antioxidative properties of a Korean steamed-rice cake, Sulgidduk added with Prunus yedoensis Matsumura extract, and vitamin C. Sulgidduk was prepared by adding Prunus yedoensis Matsumura extract at 0, 0.1, 0.2, and 0.3% of rice powder. Antioxidant activities were measured by the scavenging activities of DPPH radicals, $ABTS^+$ radicals, $superoxide^-$ radicals and the reducing power. For analyzing quality characteristics, proximate composition, color, texture profile analysis, and sensory evaluations were measured. The antioxidative effect of the Sulgidduk significantly increased as the addition level increased, compared to the original Sulgidduk (p<0.001). As the content of Prunus yedoensis Matsumura extracts increased, L-values significantly decreased while the a-value and b-value significantly increased (p<0.001). For the texture profile analysis, the control group had a significantly higher value for hardness as compared to the Prunus yedoensis Matsumura extract-added groups (p<0.05). Springiness, chewiness and adhesiveness were not significantly different among the samples. In the sensory evaluation, the samples containing 0.1% and 0.2% Prunus yedoensis Matsumura extracts obtained better results in attribute. From these results, we suggest that Prunus yedoensis Matsumura is a good ingredient for increasing the consumer acceptability and the functionality of Sulgidduk.