: Fatty liver disease and obesity are among the most prevalent health conditions in modern society and have recently garnered significant attention. Semaglutide, a well-known anti-obesity drug, has been widely used for diabetes and obesity treatment; however, nanotherapeutics utilizing semaglutide have not yet been developed. : A novel statin-lipid conjugate was synthesized using rosuvastatin and ursodeoxycholic acid, a liver-protective agent. This conjugate was then formulated with semaglutide through hydrophobic interactions to create a new nanoparticle system. The physicochemical properties of the nanoparticles were analyzed, and their therapeutic efficacy was evaluated in a high-fat diet (HFD)-induced animal model. : The statin-lipid conjugate was successfully synthesized, forming novel nanoparticles with semaglutide in an aqueous solution. These nanoparticles exhibited distinct properties compared to conventional semaglutide formulations. In animal experiments, the treatment group demonstrated a 30.24% reduction in body weight and a 46.80% improvement in liver function markers compared to the control group. : This study introduces a novel semaglutide-based nanoparticle (SRLC NP) system that overcomes key limitations of conventional semaglutide therapy by providing enhanced bioavailability, extended circulation time, and improved cellular uptake. These findings highlight the potential of SRLC NPs as a clinically translatable nanotherapeutic approach for more effective, sustained, and patient-friendly obesity and fatty liver disease treatment.