This study investigated the effect of guarana on plasma lipid metabolites in obese rats and analyzed its mechanism in the treatment of dyslipidemia in obesity. High-fat diet was used to establish obese rat models, and the therapeutic effect of guarana on obese rats was evaluated by measuring body weight, white fat, liver weight, and lipid content, as well as observing liver histomorphology. Lipid metabolites in plasma of rats in each group were detected by UHPLC-Q-TOF-MS lipidomics. The protein expressions of fatty acid synthase, acetyl-CoA carboxylase 1, triglyceride synthesis enzyme, carnitine palmitoyltransferase Ⅰ, and acetyl-coenzyme A acyltransferase 2 in rat liver were detected using Western blot. The results revealed that guarana significantly reduced body weight, white fat, and liver weight of obese rats due to high-fat diet, and alleviated dyslipidemia and liver steatosis. Lipidomics showed that some triglycerides and phospholipids were significantly elevated in the high-fat model group, and part of them was reduced after guarana treatment. Western blot found that guarana inhibited the expression of hepatic fatty acid and triglyceride synthesis-related proteins and increased the expression of fatty acid β-oxidation-related proteins. Abnormalities in triglyceride and phospholipid metabolism are the main characteristics of plasma lipid metabolism in obese rats induced by high-fat diet. Guarana may regulate partial triglyceride and phospholipid metabolism by inhibiting hepatic fatty acid and triglyceride synthesis and increasing fatty acid β-oxidation, thereby improving rat obesity and dyslipidemia.