To investigate the composition and changes of metabolites in fresh grass carp muscle during refrigeration， non-targeted metabolomics was used to systematically detect the metabolites in grass carp muscle that was refrigerated for 3 (D3)， 6 (D6)， 9 (D9) and 12 d (D12). A total of 924 metabolites were identified during the refrigeration process of grass carp muscle， including 14 types of compounds， such as lipids， organic acids and their derivatives， and organic heterocyclic compounds. Lipids were the most abundant small molecule metabolites， accounting for 39.02% of the total number of metabolites， followed by organic acids and their derivatives， accounting for 20.44%， and other metabolites accounted for less than 10%. The results of multivariate statistical analysis showed that there was no significant difference in the metabolic profile of grass carp muscle from fresh grass carp muscle on the 3rd day of refrigeration (P>0.05). However， on the 9th and 12th day of refrigeration， the metabolic profile of grass carp muscle changed significantly， and the lipid metabolites decreased significantly and organic acids and their derivatives increased significantly (P<0.05). It indicated that the metabolism of refrigerated grass carp muscle had a significant deterioration. The results of volcanic map analysis showed that with the extension of refrigeration time， the up-regulated metabolites in grass carp muscle increased significantly， especially those related to oxidative phosphorylation， such as ATP and NADH (P<0.05)， while the metabolites related to lipid metabolism， such as palmitoylcarnitine， were significantly down-regulated (P<0.05) It indicated that the energy metabolism and lipid degradation processes of grass carp muscle changed significantly during the refrigeration process. KEGG pathway enrichment analysis of differential metabolites in refrigerated grass carp muscle showed that 66， 64， 66， and 61 metabolic pathways were detected in D3， D6， D9 and D12 groups， respectively， and 18， 20， 11， and 10 pathways were significantly different compared with the fresh grass carp muscle group (P<0.05). The main metabolic pathways affecting the refrigeration of fresh grass carp muscle were oxidative phosphorylation， nucleotide metabolism， thiamine metabolism， and citric acid cycle. The research can provide a theoretical reference for the application of fresh grass carp muscle in the cold storage processing field.