Under the condition of using strains of Aspergillus oryzae and Lactobacillus plantarum WZ011,we investigated five different solid state fermentation processes used in soybean meal production and further compared the nutritional quality of respective soybean meal.Based on the indexes of ash content,crude protein content,soluble protein content,free total amino acid content,free amino acid distribution,acid soluble protein content,small peptides content,reducing sugar content,nitrogen solubility,the protein molecular weight,urease content,trypsin inhibitors content and in vitro digestion rate,soybean meal nutritional quality was compared and analyzed.The results demonstrated that soybean meal nutritional quality could be improved effectively with treatment by high temperature hydrolysis after fermentation by single Aspergillus oryzae.However,the effect of high temperature hydrolysis treatment was adverse in a process in series by Aspergillus oryzae fermentation and L.plantarum WZ011 fermentation.The fermented soybean meal was optimal in nutritional indexes when it was inoculated anaerobically by L.plantarum WZ011 after aerobic fermentation by Aspergillus oryzae.Its trypsin inhibitor content was reduced by 91.8%,compared with raw soybean meal.It also contained 8.01% small peptides,4.95% lactic acid,0.317 mg/g γ-aminobutyric acid and 1.93×1010 CFU/g L.plantarum viable count.The optimal soybean meal fermentation process was simple and pollution-free in operation.Its product was also rich in nutrition.This fermentation technology could be applied in feed processing industry and farming.