Abstract: Peanut peptide was made through solid state fermentation with Aspergillus oryzae on peanut meal and combination of enzymatic and freeze-drying technology. In the growth-promoting experiments, 0.5% peanut peptide (Mw<3ku) gave better activity on Lactobicillus bulgaricus, including that the number of viable cells raised by an order of magnitude, better coagulatin effects and increased acetaldehyde contents. Comparison of amino acid revealed that the contents and composition were improved through the method, including that the contents of essential amino acids (33.61²26.33mg/g) for Lactobacillus bulgaricus were observed.