Abstract Body (Do not enter title and authors here): Background and Objective: Diabetes mellitus (DM) is a chronic metabolic condition that can cause serious damage to blood vessels and the heart. While current metabolomics research mainly focused on metabolic profiles during disease onset or at advanced stages, there remains a gap in understanding the molecular mechanisms of metabolites in the progression of diabetic cardiovascular disease. This study aims to explore effective strategies for preventing cardiovascular complications in diabetics by excavating metabolic pathways and mechanisms. Methods: Peripheral blood samples were obtained from 21 healthy individuals, 20 patients diagnosed with DM, 20 patients with coronary heart disease (CHD), and 25 patients with both DM and CHD (DC). Cardiac function, biochemical parameters and serum metabolome were detected. A specialized methodology with rigorous screening criteria was employed to identify differential metabolites associated with diabetes-induced CHD and cardiomyopathy. Mice were injected with LPC16:0 to assess cardiovascular function. Models of diabetes and diabetic atherosclerosis were induced by STZ injection and high-fat diet feeding in WT and ApoE^-/- mice. Cardiac function and differential metabolites in aortic and cardiac tissues were assessed. The effect and molecular mechanism of LYPLA1 on vascular function, mitochondrial function, and metabolites-related enzymes were examined in human aortic endothelial cells (HAECs) and AC16 cardiomyocytes. Results: Cardiac function was markedly declined in DM and DC patients, as well as in mice with diabetes and diabetic atherosclerosis. However, CHD patients and atherosclerosis alone did not exhibit evident cardiac dysfunction. Key metabolites associated with diabetic cardiomyopathy and diabetes-induced CHD were identified as LPE18:1 and LPC16:0, respectively. Intraperitoneal administration of LPC16:0 in mice led to decreased LYPLA1, severe myocardial anomalies, and the appearance of plaques in the aortic arch. Either LYPLA1 knockdown or the treatment with high glucose and palmitic acid in HAECs resulted in impaired mitochondrial function, reduced intracellular NO and eNOS activity, which were mitigated by LYPLA1 overexpression. Conclusion: The metabolite LPC16:0 and the regulatory enzyme LYPLA1 are pivotal in driving the advancement of cardiovascular complications triggered by diabetes. Targeting LYPLA1 could represent a promising strategy for preventing diabetes-induced CHD and subsequent cardiomyopathy.