Sericin　peptides　have　a　high　proportion　of　hydrophilic　amino　acid　residues,　which　are　considered　to　protect　cells　from　freezing　stress　due　to　the　maintenance　of　water　in　the　cells.　In　this　paper,　the　hypothermia　protection　effect　of　sericin　peptides　was　studied　by　reading　optical　density　of　cells　at　600　nm,　which　was　detailedly　optimized　to　be　a　direct　and　practical　spectrophotometric　method.　The　survival　rate　of　Lactobacillus　bulgaricus　after　frozen　storaged　with　addition　of　0.1　mg/mL　sericin　peptides　was　close　to　that　of　10%　(v/v)　glycerol　(p　＞　0.05).　The　survival　rate　of　5　mg/mL　sericin　peptides　was　up　to　64.17%.　©　(2013)　Trans　Tech　Publications,　Switzerland.