Based on the first principles, the materials studio software was used to simulate the energy band structure, density of states, and optics properties of 2H-MoS2. The results show that MoS2 was an indirect band gap semiconductor with a band gap of about 1.25eV; the material had a certain absorption in the ultraviolet to visible wavelength range, and the absorption coefficient decreases with the increase of wavelength. Raman spectra showed E12g and A1g vibration modes at 375 and 400cm-1, respectively. Typical diffraction peaks such as (103) and (101) appeared at the positions 39.5° and 33.5°. Magnetron sputtering method was also used to prepare MoS2 films with different thicknesses on a quartz substrate in this paper. It was found that the film had (101) preferred orientation, E12g and A1g were also presented at 375 and 407cm-1 in the Raman spectrum. As the film thickness increased, the transmittance of the film in the visible light band decreased, and the optical band gap shifted toward longer wavelengths. The simulation results were basically in agreement with the experimental results.