Abstract: Opened oyster sauce is susceptible to contamination by Aspergillus chevalieri and deterioration under ambient conditions. In order to investigate the detailed process of oyster oil mould, we measured the basic physicochemical indexes of oyster oil samples simulating deterioration, and analyzed the differences and changing rules of metabolites in the deterioration process of oyster oil by using non-targeted metabolomics approach. The results show that the total protease activity, α-amylase activity, moisture, total acid and volatile saline nitrogen of oyster oil during the deterioration process showed an increasing trend, but the contents of sugars, proteins and total free amino acids decreased. A total of 618 metabolites were identified from the oyster oil samples, which were mainly classified into 14 groups, including lipids and lipid-like molecules, organic acids and their derivatives, organic oxygen compounds and organic heterocyclic compounds. Orthogonal Partial Least Squares Discriminant Analysis (OPLS-DA) model was used to screen the metabolites for significant differences, and the screening criteria were: value of variable importance in the projection (VIP) ≥1, p-value<0.05, and the fold change (FC)>2 or <1/2. A total of 21 metabolites were screened under these criteria, of which 10 were up-regulated metabolites and 11 were down-regulated metabolites. The pathway enrichment analysis of Kyoto Encyclopedia of Genes and Genomes (KEGG) showed that the differential metabolites were mainly involved in starch and sucrose metabolism, lipid metabolism, lysine degradation, nucleotide metabolism, and other related pathways, which suggests that there are differences in the consumption of each nutrient in the process of oyster oil deterioration.