The　ultrathin　feature　of　two-dimensional　(2D)　transition　metal　dichalcogenides　(TMDs)　has　brought　special　performance　in　electronic　and　optoelectronic　fields.　When　vertical　and　lateral　heterojunctions　are　made　using　different　TMD　combinations,　the　original　properties　of　premier　TMDs　can　be　optimized.　Especially　for　lateral　heterojunctions,　their　sharp　interface　signifies　a　narrow　space　charge　region,　leading　to　a　strong　in-plane　built-in　electric　field,　which　may　contribute　to　high　separation　efficiency　of　photogenerated　carriers,　good　rectification　behavior,　self-powered　photoelectric　device　construction,　etc.　However,　due　to　the　poor　controllability　over　the　synthesis　process,　obtaining　a　clean　and　sharp　interface　of　the　lateral　heterojunction　is　still　a　challenge.　Herein,　we　propose　a　simple　chemical　vapor　deposition　(CVD)　method,　which　can　effectively　separate　the　growth　process　of　different　TMDs,　thus　resulting　in　good　regulation　of　the　composition　change　at　the　junction　region.　By　this　method,　MoS2-WS2　lateral　heterojunctions　with　sharp　interfaces　have　been　obtained　with　good　rectification　characteristics,　similar　to　105　on/off　ratio,　1874%　external　quantum　efficiency,　and　similar　to　120　ms　photoresponse　speed,　exhibiting　a　better　photoelectric　performance　than　that　of　the　lateral　ones　with　graded　junctions.