Wafer sized, high quality continuous films would be a key demand for MoS2 implemented in circuit application. In this study, the growth of few monolayer MoS2 on 4 inches SiO2/Si substrate were demonstrated. The MoS2 thin films were synthesized by sulfurized in a furnace from the ultra-thin MoO3 starting materials by using H2S. The obtained MoS2 thin film examined by Raman analysis and Photoluminescence (PL), shows the semiconductor nature with direct transition peaks of 1.86 eV and 1.99 eV. The 4∼5 monolayer of MoS2 with thickness around 2.6 nm is confirmed by cross-sectional view of transmission electron microscopy (TEM). Additionally, the DC characteristics of MoS2 MOSFETs exhibit at least 2 order in on/off current ratio, demonstrating the feasibility for circuit application.