In order to establish the optimal semi-solid fermentation conditions of defatted rice bran fermented by lactic acid bacteria and clarify the change of nutritional value of defatted rice bran before and after fermentation， the effect of lactic acid bacteria fermentation on the content of reducing sugars and soluble phenolics was chosen as the evaluation parameter in this paper. The results showed that Lactobacillus acidophilus and Lactobacillus plantarum selected as complex lactic acid bacteria had the best ability in reducing sugars and releasing phenolics during the fermentation of defatted rice bran. The optimal fermentation conditions were obtained through the single factor experiment as follows： 5.0% inoculation amount of complex lactic acid bacteria， ratio of strains 1∶1， fermentation temperature 35 ℃， fermentation time 36 h. Compared to the unfermented group， the soluble solid， carbohydrate， soluble dietary fiber， protein and total soluble phenolics content in fermented defatted rice bran was increased by 31.42%， 21.82%， 112.21%， 65.54% and 37.14%， respectively（P<0.05）. Moreover， the content of essential amid acid in protein of fermented defatted rice bran extract was increased by 21.23%， of which isoleucine， leucine， lysine， methionine， phenylalanine， valine was increased by 47.18%， 49.78%， 13.73%， 9.0%， 75.26%， 24.06%， respectively （P<0.05）. Meanwhile， the ratio of essential amino acid（EAA） to nonessential amino acid （NEAA） of fermented defatted rice bran extract was 0.48， and the score of ratio coefficient（SRC） of essential amino acid was closer to 100. The above results indicated that lactic acid bacteria fermentation significantly improved the nutrition value of defatted rice bran. This study could provide theoretical basis for biological utilization with high value of defatted rice bran.