In order to select the most important nutrients that influence the production of cell-envelope proteinase (CEP), Plackett-Burman design was employed to assess the effects of glucose, maltose, peptone, casein peptone, inulin, isomaltooligosaccharide, Na2HPO4, CH3COONa, leucine, and serine on the activity of CEP, protein content, specific activity, optical density (OD600) value and pH in MRS broth fermented by Lactobacillus plantarum LP69. The results revealed that Na2HPO4, inulin, casein peptone and leucine significantly affect (P<0.05) the production of CEP. Additionally, Na2HPO4, inulin and leucine were negatively correlated with the enzyme activity and the specific activity, while casein peptone was positively correlated with the enzyme activity and the specific activity.