The invention belongs to the technical field of medicines and relates to an artocarpus nitidus extract and a use thereof. The extract is prepared by taking stems and branches of artocarpus nitidus as raw materials, using alcohol and/or water extraction for obtaining a total extract, further dissolving the total extract in water, respectively extracting with solvents of petroleum ether, chloroform or dichloromethane, taking extraction phase of the chloroform or the dichloromethane, recovering the solvents and drying. The content of isopentenyl substituted flavonoids and arylbenzofuran compounds in the extract is 30%-60%. The results of the in vitro pancreatic lipase activity testing and the animal in vivo experiments prove that the extract has obvious pancreatic lipase activity inhibition role and the weight-reducing role, and can be used for preparing drugs for preventing or treating clinical common frequent obesity and the relevant metabolic diseases.