The principal objective of this study was to determine the quality and potential of DHEA formation after the addition of diosgenin of yam(Dioscorea spp.) during the fermentation of soybean paste. All samples were divided into three groups based on the variety of yam. In sample A, the soy source was not separated from soybean paste and in sample B, the soybean source was separated from soybean paste. The range in salt concentration in the samples was as follows : sample A: 10.5~11.8%, samples B: 7.9~8.8%. However, no substantial differences between the two samples, in terms of salt content, were observed. The crude protein and crude lipid content were found to decrease with the fermentation time of soybean paste(passage of 30 days: 26.4~32.3% and 4.45~5.90%, passage of 60 days: 24.5~28.5% and 3.95~4.90%, respectively). As the fermentation time of soybean paste increased, the nitrogen from amino compounds increased(passage of 30 days: 531.9~687.7 mg%, passage of 60 days: 551.3~706.8 mg%). In regards to color and preference, sample B, where the soy source was separated from soybean paste, was better than sample A, where the two components were not separated. After a soybean paste fermentation time of 60 days, the diosgenin of yam, which was added to the soybean paste, was not detected in tested samples, and the contents of DHEA formation in soybean paste were as follows: sample A: $488.0pm42.5{sim}719.3pm44.8{mu}g/g$, sample B: $287.3pm20.6{sim}482.7{pm}36.5{mu}g/g$.