Objective: The effects of different wall materials on the preparation of Bifidobacterium lactis Probio-M8 microcapsules by vacuum low-temperature spray drying were studied in this study. Method: The solubility， rehydration time， powder fluidity， and the physical properties of the powder moisture and water activity of the microcapsule powder with different wall materials were measured by physical methods， and the changes in the integrity of the bacterial cell membrane before and after drying were observed using a fluorescence microscope. The morphology and structure of the microcapsule powder were observed by scanning electron microscope and the glass transition temperature of the microcapsule powder was measured with a differential scanning calorimeter. The DPPH free radical scavenging ability and total antioxidant capacity of different wall materials to protect the bacteria were measured. Results: The Probio-M8 microcapsule powder of composite wall material showed a higher survival rate of 73.8%， and had a lower water content(4.85%) and water activity(0.17)， and the powder had excellent fluidity. But due to the complex composition of the composite wall material， the microcapsule powder of the composite wall material had lower solubility and longer rehydration time than the three kinds of microcapsule powders. In addition， the integrity of the Probio-M8 cell membrane protected by the composite wall material was also higher than that of the Probio-M8 protected by the other three wall materials， which effectively protects the integrity of the bacterial cell membrane. Furthermore， the Probio-M8 microcapsule powder of composite wall material had a higher glass transition temperature and a higher glass transition temperature and strong antioxidant capacity which is beneficial to the storage stability of Probio-M8 microcapsule powder. Conclusion: This experiment compared the effects of different wall materials on the bacterial activity after spray drying of Probio-M8， and found that different wall materials have different protective effects on the bacterial cells. Among them， the composite wall material can protect the bacterial cells more effectively. Which has certain reference significance for the industrial production of Bifidobacterium lactis Probio-M8 microcapsules.