Abstract: The viability of probiotics can dominate the probiotic efficacy of products in the industrial production of probiotic preparations. Probiotics have been usually prepared in dry powder form for easy transportation and storage, in order to ensure a sufficient number of viable bacteria. Vacuum freeze drying can be often used for probiotic preparations in the industry at present. Nevertheless, the strain can be damaged inevitably during the vacuum freeze drying. The survival rate of the strain during the freeze drying can be improved to change the composition of the culture medium. One of the common growth factors, the uracil has often been added to the culture medium for the high proliferation of strains. Taking the uracil as the study material, this study aims to investigate the effect of adding trace growth factors to the medium on the freeze drying survival of the strain. The Lactiplantibacillus plantarum LIP-1was selected to isolate from Xinjiang sour mare milk with the probiotic effect. Firstly, the different concentrations of the uracil culture medium were configured to determine the optimal amount of uracil, where the freeze drying survival rate was taken as the index. Next, the optimal concentration group of uracil was set as the experimental group and the group without uracil as the control group. Finally, the cell damage of the strain was evaluated to clarify the influencing mechanism of uracil on the freeze drying survival rate of the Lactiplantibacillus plantarum LIP-1. The results showed that the addition of 0.05 g/L uracil to the culture medium significantly improved the number of viable bacteria and freeze drying survival rate of Lactiplantibacillus plantarum LIP-1 (P<0.05). The cell wall and cell membrane of Lactiplantibacillus plantarum LIP-1 after freeze drying were measured by Fourier infrared spectroscopy. In addition, the damage level to the cell wall and cell membrane of Lactiplantibacillus plantarum LIP-1 was evaluated after freeze drying by the lysozyme and NaCl sensitivity assay. The experimental results showed that the addition of 0.05 g/L uracil to the medium reduced the damage to the cell wall and cell membrane of the strain during the freeze drying. The whole genome sequencing of Lactiplantibacillus plantarum LIP-1 combined with real-time fluorescence quantitative PCR was selected to explore the internal mechanism. It was found that the addition of uracil increased the relative expression of UPRT and pyrH (P<0.05), which was the key gene for the uracil synthesis of UDP, and increased the relative expression of glmU (P<0.05), the key gene expressed by UDP GlcNAc, and the precursor of peptidoglycan synthesis (P<0.05), indicating the sufficient raw materials for the peptidoglycan synthesis. Thus, the content of peptidoglycan increased during the process. The increase of peptidoglycan content enhanced the stability of the cell wall. At the same time, the addition of uracil inhibited the relative expression of pyrE (P<0.05), a key gene for the conversion of orotic acid to uridine diphosphate, resulting in an increase in the intracellular content of orotic acid (P<0.05). It infers that the antioxidant capacity was reduced the degree of oxidation of unsaturated fatty acids in the cell membrane by reactive oxygen species, thereby reducing the degree of damage to the cell membrane of the strain. The strain reduced the freeze drying damage to the cell wall and cell membrane by metabolizing uracil, indicating the improved freeze drying survival rate of the strain. This finding can also provide a new idea for the high survival rate of the strain during vacuum freeze drying.