Abstract: Leptin is a peptide hormone encoded by fat gene and secreted by adipose tissue. Leptin binds to leptin receptor and activates a variety of signal transduction pathways, playing a role in regulating energy metabolism and appetite suppression. Leptin resistance is present in most obese patients, in which leptin level increased but effect diminished or disappeared. The mechanism of leptin resistance is related to many factors and not fully elucidated now, but its main reason is the post-receptor signal transduction disorder. Therefore, the study on leptin signaling pathways and leptin resistance is important to propose strategies to overcome leptin resistance and thus to prevent and control obesity.