Based on first-principles with the generalized gradient approximation (GGA) of the Perdew-Burke-Ernzerhof (PBE) form, the authors carry out systematic investigations regarding the electronic structures and optical properties of zinc-blende (ZB) ZnS doped with six types of transition metals. The Cd-doped system has greater structural stability with a lower formation energy of 0.526eV compared to other systems. Additionally, the band structures of systems are employed to show the superior semiconductor capacity of Mo- and Pt-doped systems with decreased band gaps (E-G) of 0.978eV and 0.843eV, which are smaller than those of the pure system and others. Moreover, charge difference density maps show that the covalent properties of MoS and PtS bonds are enhanced by exposing the electron-deficient region. Meantime, optical properties, including absorption and reflectivity spectra, dielectric constant, and loss function, are introduced to reveal that the absorption spectra curves reach the lowest absorption peak of 2.375x10(5)cm(-1) at 7.227eV for the Mo-doped system, in which the system exhibits a relatively negative reflectivity spectrum and dielectric loss that is expected in the solar cell industry, predicting its broad scope of application prospects in the photoelectric and microelectronic device fields.