Transition　metal　dichalcogenide　(TMDC)　monolayers　exhibit　enhanced　electrical　and　optoelectrical　properties,　which　are　promising　for　next-generation　optoelectronic　devices.　However,　large-scale　and　uniform　growth　of　TMDC　monolayers　with　large　grain　size　is　still　a　considerable　challenge.　Presented　in　this　work　is　a　simple　and　effective　approach　to　fabricating　largescale　molybdenum　(MoS2)　disulfide　monolayers　by　chemical　vapor　deposition　(CVD)　method.　It　is　found　that　MoS2　grows　from　single　crystal　into　thin　film　with　the　increase　of　oxide　precursor　proportion.　The　photodetector　of　large　scale　monolayer　layer　MoS2　film　is　fabricated　by　depositing　metal　electrodes　on　the　interdigital　electrode　mask　through　using　thermal　evaporation　coating.　Finally,　the　highly　stable　and　repeatable　photoelectric　responses　under　the　conditions　of　different　voltages　and　different　laser　power　are　characterized　under　405-nm　laser　excitation,　with　response　time　decreasing　down　to　the　order　of　milliseconds　(ms).　In　addition,　the　photodetector　achieves　a　wide　spectral　detection　range　from　405　nm　to　830　nm,　that　is,　from　visible　light　to　near-infrared　light　wavelength　range,　with　optical　response　(R)　of　291.7　mA/W　and　optical　detection　rate　(D*)　of　1.629x109　Jones.　The　monolayer　MoS2　thin　film　photodetector　demonstrated　here　has　the　advantages　of　low　cost,　feasibility　of　large-scale　preparation,　and　good　stability　and　repeatability　in　the　wide　spectrum　range　from　visible　light　to　near　infrared　light　wavelength,　providing　the　possibilities　for　future　applications　of　electronic　and　optoelectronic　devices　.