Abstract: In order to investigate the types of microorganisms in commercially sold pork tenderloin, and the effects of different storage temperatures in refrigerators on the types and abundance of microorganisms, the commercial pork tenderloin was taken as the research object and avoiding external microbial contamination during the period of segmentation, packaging and storage, and then the samples were kept at 25, 4,-3.5,-18,-32 ℃ for 24 hours respectively. The microorganisms on the surface of the samples at same storage temperature were dipped with sterile toothpick, and cultured in three selective media of bacteria, yeast and mold, the mixture of bacteria, yeast and mold was obtained by washing from Petri dish. Using 16S rRNA and ITS sequencing methods to determine the types of bacteria, yeast, and mold in the above samples, and analyze their relative abundance. In order to further study the microbial species of the above pork tenderloin in the home freezer（-18 ℃）, the microorganisms of the samples stored at-18 ℃ were isolated,purified and sequenced. The isolated strains could provide target strains for future sterilization research in the freezer.The results showed that the marketed pork tenderloin contained many microorganisms, mostly bacteria, followed by yeast, and less mold. With the the change of storage temperatures, the species and abundance of microorganisms would also change significantly. The sequencing results of purified microorganisms at-18 ℃ showed that pork tenderloin still contained a small number of cold resistant microorganisms under freezing conditions, and there was still a risk of spoilage in long-term frozen storage.