. Dried Porphyra yezoensis is raw material for roasted laver. Its microbial species and content directly affect the food safety of the final product. In order to investigate the changes in bacterial diversity during the processing of dried Porphyra yezoensis and to identify dominant bacteria that contribute to elevated bacterial counts, this study monitored the total number of bacterial colonies in the critical process, analyzed the changes in the total bacterial flora and culturable bacterial flora through high-throughput sequencing technology, and conducted strain identification and tolerance characteristics analysis of the dominant bacteria. The results showed a decrease in bacterial numbers after washing process of original seaweed. After drying treatment, the total number of bacterial colonies in the samples changed inconsistently, and the sterilization effect during the drying process was not significant. The original seaweed harbored a diverse bacterial community, with relatively high abundances of Olleya, Maribacter, Octadecabacter, Sulfitobacter, etc. There were significant differences in bacterial community structures from different harvesting areas. After drying, the diversity of the total bacterial community decreased with Cyanobacteria becoming the dominant bacteria. The culturable dominant bacteria included Macrococcus, Deinococcus, Bacillus, Acinetobacter, Chryseobacterium, etc. The isolated dominant bacteria, Macrococcus, exhibited poor temperature tolerance but strong drought resistance. This study revealed the critical processing stages leading to increased bacterial counts in dried Porphyra yezoensis and the changes in bacterial communities during processing, and preliminary illustrated the tolerance characteristics of dominant bacteria. These results provided the basis for the control of microbial content in the processing of enterprises, and also laid a theoretical foundation for further research and development on control techniques for the bacteria in dried Porphyra yezoensis.