Soybean [Glycine max L. (Merr.)] is an important legume crop, with an annual global production of 367.8 million tons. The seeds contain about 20% oil of dry weight, which is mainly used for oil extraction, and the improvement of soybean oil quality is a critical subject world-wide. We isolated several fatty acid accumulation mutants and identified the corresponding genes. Next, we attempted to improve the soybean oil quality using these mutant genes. We successfully developed a novel high-oleic acid soybean cultivar, "SADAIEICHIOICHIGOU", from which oil with an oleic acid content as high as 80 % of total fatty acids was obtained. Moreover, the linoleic acid content of "SADAIEICHIOICHIGOU" was obviously low. The oil extracted from this cultivar showed higher oxidation stability than conventional varieties and had decreased levels of the unpleasant green off-odor of soybeans. In addition, we isolated a novel mutant that does not accumulate furan fatty acids, associated with a hay-like odor, and identified the corresponding gene. This series of soybean fatty acid mutants have great potential to improve the nutritional value, functionality, palatability, and oxidative stability of soybean-based food.