Soybean curds were prepared by adding different levels (20, 40, and 60%) of small black soybean, and the quality characteristics of the soybean curds were investigated. The yield of soybean curd increased slightly with the increment of the levels of small black soybean, whereas L value (lightness) and b value (yellowness) decreased. Analysis of textural properties demonstrated that the addition of small black soybean lowered the hardness and chewiness of soybean curd, while it slightly increased the cohesiveness and adhesiveness. Antioxidant activities of soybean curd, soybean curd residue, and soybean curd whey were estimated by determining electron donating ability (EDA) to DPPH radical and superoxide dismutase (SOD)-like activity. These activities in all of the samples increased with the addition of small black soybean, especially in soybean curd residue and soybean curd whey; also, soybean curd whey containing small black soybean showed the highest activities.