We confirmed the character impact compounds of the flavors of the soybean paste manufactured with the traditional and improved Meju, respectively, by using the following methods: gas chromatography (GC), sniffing tests and GC-mass. The soybean paste made with the traditional Meju had 12 compound groups that smelled like the soybean paste flavor, whereas the soybean paste made with the improved Meju had 7 compound groups of soybean paste flavor smell. We were easily able to determine that there is a difference of soybean paste flavor compounds between the soybean pastes made with either the traditional or the improved Mejus because the two soybean paste flavors are very different from each other.