<p>Two-dimensional heterostructures have become a research focus in materials science, driven by their flexible and adjustable electronic, magnetic, and optical characteristics. As materials with significant potential for optoelectronic and spintronic devices, they exhibit a wide range of application prospects. However, the inherent non-magnetic properties of the SnS₂/MoS₂ heterostructure pose a significant constraint on its potential applications within the realm of spintronics. Therefore, the incorporation of transition metals to impart magnetism is crucial for further expanding the boundaries of spintronic applications. In the present study, we employed first-principles calculations to conduct an in-depth analysis of the photoelectric and magnetic properties of TM/SnS₂/MoS₂ heterostructures, where transition metal (TM = Mn, Fe, Co, Ni, Cu) atoms replace Sn atoms in the heterostructure. The results of the study are as follows: when doped with Mn and Co, the SnS₂/MoS₂ heterostructure exhibits half-metallic properties; when doped with Fe and Cu, it shows characteristics of a magnetic semiconductor; and when doped with Ni, it behaves as a non-magnetic semiconductor. Additionally, the doping of transition metals increases the static dielectric constant and results in the light absorption edge shifting toward longer wavelengths, a phenomenon known as redshift. Therefore, transition metal doping is shown to effectively regulate both the optoelectronic and spintronic characteristics of the SnS₂/MoS₂ heterostructure. The theoretical insights derived from this study lay a foundational framework for the practical deployment of TM/SnS₂/MoS₂ heterostructures in optoelectronic and spintronic technologies, indicating that such heterostructures are promising candidates for high-quality spintronic and optoelectronic devices.</p>