A soybean cultivar ‘Yonpoong’ which has safety high yield for double cropping system introduced winter forage crop was released by agricultural resource research institute of ARES, Gyeunggi Province in 2010. The goals of breeding were for large seed size, high yield, and resistance to disease such as spotting disease. ‘Yonpoong’ was derived from the cross of ‘Suwon 191’, which large seed size and high yield, and ‘Suwon 126’, which early maturity cultivar, and short stem. The preliminary, advanced and regional yield trials for evaluation and selection were carried out from 2005 to 2010. ‘Yonpoong’ has a determinate growth habit with purple flower, grey pubescence, brown pod color, yellow seed coat, yellow cotyledon, elongated seed shape, large seed size(28.7 g per 100 seeds). The maturing date was sept. 22. Tofu yield was similar to that of check cultivar ‘Daewonkong’. The average yield of ‘Yonpoong’ was 3.34 MT/ha in the regional yield trials(RTY) carried out in Korea from 2008 to 2010 which 38 percent higher than the check cultivar ‘Daewonkong’.