Objective Macro-genomics technology was applied to explore the changes in microbial community structure and diversity on the surface of chilled pork at different stages and to analyze the composition and changes of risky bacteria， to provide a reference for the control of risky bacteria in chilled meat.Methods Macro-genomics technology was used to perform sequencing on 30 chilled pork samples at three stages： pre-cooling， post-mortem ageing， and marketing， and to analyze changes in microbial diversity and metabolic pathways of the flora.Results There were significant differences in the flora structure of chilled pork at different stages. From pre-cooling to acid excretion to marketing， the relative abundance of Rhizobium caused an increase and then a decrease in the relative abundance of Proteobacteria. The increase in the abundance of Brochothrix caused a gradual increase in the abundance of Firmicutes. The PCoA analysis showed that the acid-drainage pork partially overlapped with the commercially available pork， suggesting that the bacteria were similar. The relative abundance of the dominant spoilage bacteria， Brochothrix thermosphacta， Pseudomonas fragi， and Acinetobacter baumannii， was significantly increased in the samples from acid-expelled to commercially available meat. Metabolic pathway analyses indicated that the abundance of genes encoding bacteria related to metabolism annotated in the acid-expelled meat samples was the highest among the three stages of samples， the abundance of some of the proteins and enzymes that coordinate sugar metabolism and amino acid metabolism showed an increasing trend in the three groups of samples， and there was consistency with the trend of changes in Brochothrix and Pseudomonas.Conclusion The bacterial populations in the samples of aged meat were similar to those in the samples of saled meat， and the control of bacterial populations during post-mortem ageing should be strengthened during production， while appropriate measures should be taken to control the propagation of spoilage bacteria， to guarantee the quality and safety of meat in the process of supply chain.