In this study, two dimensions (2D) of MoS2: W thin films were deposited by spray pyrolysis on glass substrate at T=400 °C by changing the concentration of tungsten trioxide as [W/Mo] = 0.01, 0.05, 0.15 and, 0.2. The annealing process under sulfuration for MoS2: W thin films were studied with sulfur (S) concentration ratio of [S/Mo]=2. Thiourea ((H2N) CS (NH2)) precursors were used as sulfur sources and WO3 as tungsten source for thin films. After preparing thin films, the effect of tungsten (W) concentration and annealing on the structural, optical absorbance and tunning of band gap of MoS2: W thin films was studied. The XRD results showed that sulfur-free thin films had an orthorhombic structure and after sulfurization a hexagonal structure. Also, the size of the nanocrystals for (002) preferred peak increased as considerably with increasing concentration of tungsten (W) up to 15%W. The surface images of thin films by FE-SEM showed that the morphology of crystals changed after annealing and sulfurization. Also, the behavior of absorption coefficient (α) and extinction coefficient (k) in terms of wavelength in the UV-Vis region has been studied. The energy gap after annealing increases with increasing tungsten concentration. The optical absorption analysis showed that the direct optical gap of the thin films varies in the range ΔEg=0.66 before annealing and in the range of ΔEg=0.46 after annealing under sulfurization.