The freeze-drying method is commonly used for preparing directed vas set （DVS）. However， in the process of freeze-drying， the survival rate of bacteria decreases and the activity of starter is affected. In order to improve the survival rate of Lactobacillus acidophilus after freeze-drying， the cold shock treatment of L. acidophilus before freeze-drying was optimized by single factor experiments and response tests. The optimal cold shock treatment conditions were as follows. L. acidophilus were incubated in MRS broth at 37 ℃ for 10 hours， and then be treated by cold shock treatment at 8 ℃ for 15 hours combing with composite cryoprotectant. The survival rate of L.acidophilus after freeze-drying increased to 96.64% which was higher than the group adding cryoprotectant but without cold shock treatment（78.99%） as well as the group without cold shock and no cryoprotectant （21.42%）， the survival rates increased 17.65%， 75.22% respectively. The results indicate of that cold shock treatment before freeze-drying is a new effective way to improve the tolerance of lactic acid bacteria to freeze-drying stress and increasing the survival rate of lactic acid bacteria for preparation of high-activity DVS.