A metabolomics method based on ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) was applied to study the metabolic changes of liver in db/db mice administered with curcumin. After one week of acclimating to feeding, 20 db/db mice were randomly divided into two groups: curcumin non-treatment group and curcumin treatment group. After eight weeks of treatment, plasma and liver were collected for biochemical analysis and metabolomics analysis, as well as liver oxidative stress and histopathology examination. Serum biochemical indicators such as blood glucose, triglycerides, fasting insulin, and aspartate aminotransferase decreased significantly in the curcumin treatment group compared to the curcumin non-treatment group, whereas hepatic pathological levels and antioxidation levels improved. There were several different potential biomarkers in two groups, including sphingomyelin (SM) (d18:0/20:0), eicosapentaenoic acid (EPA), docosapentaenoic acid (22n-6) (DPAn-6), arachidonic acid (AA), dihomo-gamma- linolenic acid (DGLA), leukotriene C4 (LTC4), lysophosphatidylethanolamine (LysoPE) (16:1(9Z)/0:0), LysoPE (18:1(9Z)/0:0), LysoPE (0:0/18:0), LysoPE (0:0/20:1(11Z)), LysoPE (20:1(11Z)/0:0), 3-sulfinoalanine, alpha-tocotrienol (α-T3) and pantetheine 4′-phosphate (4′-PP). The mechanism might be related to biosynthesis of unsaturated fatty acids, arachidonic acid metabolism, phospholipid metabolism, and taurine and hypotaurine metabolism. The effects of curcumin on type 2 diabetes mellitus (T2DM) include antioxidant, delaying development of T2DM, preventing β-cell death, decreasing insulin resistance, alleviating hepatic damage, and improving metabolic disturbances. Our results provide novel insights and ideas for prevention and treatment of curcumin on T2DM and its complications.