Improving energy homeostasis and the gut microbiota is a promising strategy to improve obesity and related metabolic disorders. Mulberry leaf is one of the traditional Chinese medicines and functional diets. In this work, a mouse model induced by high-fat diet (HFD) was used to reveal the role of mulberry leaf polysaccharides (MLP). It was found that MLP had a significant effect in limiting body weight gain (reduced by 19.95%, 35.47% and 52.46%, respectively), ameliorating hepatic steatosis and regulating lipid metabolism in HFD induced obese mice (P < 0.05). RT-PCR and western blot analysis suggested that these metabolic improvements were mediated by inducing the development of brown-like adipocytes in inguinal white adipose tissue and enhancing brown adipose tissue activity. Besides, 16S rRNA sequencing results led to the inference that MLP could mitigate the composition and function of the gut microbiota. Together, these findings indicated that MLP possess great potential as a diet supplement or medication for obesity.