In order to explore the effect of different initial culture pH on the anti-freeze-drying activity of Lactobacillus plantarum LIP-1， the optimized medium was used as the basis， and the optimum pH was screened by single factor experiment. The groups with higher growth but significant difference in survival rate of LIP - 1 after freeze-drying were chosen to extracte the fatty acid composition of cell membrane and determine the enzyme activity of key cells. The results showed that there was no significant difference in the number of viable cells in the initial pH 6.8 and pH 7.4， which were 9.79 lg（CFU/mL） and 9.70 lg（CFU/mL）； however， the freeze-drying survival rate was significantly different （P<0.05）. They were 81.76% and 72.43% respectively. Further analysis showed that suitable initial pH culture can promote the synthesis of unsaturated fatty acids in cell membranes and ensure better enzyme activity， improve cell membrane fluidity， maintain cell integrity， reduce lyophilization of strains and enhance antifreeze drying of strains. Based on this， this study provides an important scientific basis for the study of lactic acid bacteria resistance to freeze-drying， and lays a theoretical foundation for promoting the industrial production of probiotics in China.