To clarify the main spoilage bacteria of refrigerated pork and their spoilage characteristics, and to provide theoretical support for the optimization of precision preservation technology for pork, this study focused on fresh pork refrigerated at 4 °C until the end of its spoilage stage. A total of 8 dominant spoilage bacterial strains were isolated and purified from the spoiled pork samples, including 6 Gram-positive bacilli and 2 Gram-negative bacilli. Strain identification was performed through morphological observation, Gram staining, and 16S rDNA gene sequencing. The identification results showed that 6 of the core strains were Bacillus cereus, and the other 2 belonged to the genus Proteus. Among the isolates, Bacillus cereus exhibited the highest abundance and the strongest spoilage potential, making it the dominant spoilage bacterium in the refrigerated pork. Subsequently, the screened core dominant spoilage bacterial strains were inoculated back into fresh pork tenderloin. The results indicated that the rising rates of pH value, water loss rate, and TVB-N content of the pork samples inoculated with this bacterium during the refrigerated period were significantly higher than those of the control group, and the degree of color deterioration was more severe. This study confirmed that Bacillus cereus is the key spoilage bacterium during the refrigerated storage of fresh pork.