The concentration of bioactive components was the key factor to functionality of fermented food. The object was to develop and characterize a sprouted soybeans- based fermented milk by using γ-amino butyric acid (GABA)-producing Lactobacillus plantarum S-35. Inoculation volume, fermentation time and fermentation temperature were studied as single factors affecting the yields of GABA in the fermented milk. The central composite design was used to optimize the fermentation technology. The results were analyzed with the software Design-Expert 8.0.6. Results indicated that the fermentation system model had an extremely significant effect on predicting the results of the test. Results of the response surface optimization test showed that the optimal fermentation condition was as follows: inoculation volume was 3.5%, fermentation time was 27h, and fermentation temperature was 34.5℃. The verification tests demonstrated that the actual yields of GABA was 1.61g/L, and the maximum number of viable probiotics count was 1.60×109CFU/mL. When it was stored at 4℃ after 7d, the product had good quality with sensory evaluation, viable cell numbers and pH value. The research results proposed specific processes and fermentation conditions for GABA enrichment in sprouted soybeans, which can provide a new, natural, and functional food resource.