【Abstract】Objective Investigating the interventional effect and underlying mechanism of Isaria felina (IF) on metabolic disorders in high-fat diet (HFD)-induced obese mice. Methods 30 SPF grade male Kunming mice were randomly stratified by body weight into 5 groups: control group, model group, white kidney bean group, 50 mg/kg IF group, and 100 mg/kg IF group, with 6 mice in each group. Mice in control group were fed a maintenance diet (10% kcal from fat), while mice in the other experimental groups were fed a HFD (60% kcal from fat). Mice in control group and model group received normal saline by gavage daily; mice in white kidney bean group received white kidney bean extract at 50 mg/(kg·d) by gavage; mice in 50 mg/kg IF group and 100 mg/kg IF group were administered IF at 50, and 100 mg/(kg·d) by gavage, respectively. After continuous gavage for 6 weeks, an oral glucose tolerance test (OGTT) was performed; serum levels of total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), urea (Urea) and creatinine (CRE) were measured; liver and adipose tissues were excised and weighed to calculate liver index and fat index; epididymal adipose tissue and liver tissue was stained with hematoxylin-eosin to observe histopathological changes; Oil Red O staining was employed to evaluate hepatic lipid accumulation. Results Compared with the model group, the body weight, fasting blood glucose, area under the OGTT curve, serum levels of TC, TG, LDL-C, AST, ALT, ALP, Urea and CRE, as well as the weights and indices of liver and adipose tissue were significantly reduced in mice of all IF dose groups (P < 0.05), and the abnormally elevated HDL-C was downregulated by IF. Moreover, IF alleviated the pathological adipocyte hypertrophy in epididymal adipose tissue, and mitigated hepatic steatosis and lipid accumulation. Conclusions IF has the effects of improving glucose intolerance, reducing serum lipid levels, inhibiting body fat accumulation, alleviating hepatic steatosis, and mitigating hepatorenal dysfunction in HFD-induced obese mice.