The　efficient　nondestructive　assessment　of　quality　and　homogeneity　for　two-dimensional　(2D)　MoS2　is　critically　important　to　advance　their　practical　applications.　Here,　we　presented　a　rapid　and　large-area　assessment　method　for　visually　evaluating　the　quality　and　uniformity　of　chemical　vapor　deposition　(CVD)-grown　MoS2　monolayers　simply　with　conventional　optical　microscopes.　This　was　achieved　through　one-pot　adsorbing　abundant　sulfur　particles　selectively　onto　as-grown　poorer-quality　MoS2　monolayers　in　a　CVD　system　without　any　additional　treatment.　We　further　revealed　that　this　favorable　adsorption　of　sulfur　particles　on　MoS2　originated　from　their　intrinsic　higher-density　sulfur　vacancies.　Based　on　unadsorbed　MoS2　monolayers,　superior　performance　field　effect　transistors　with　a　mobility　of　∼49　cm2　V-1　s-1　were　constructed.　Importantly,　the　assessment　approach　was　noninvasive　due　to　the　all-vapor-phase　and　moderate　adsorption-desorption　process.　Our　work　offers　a　new　route　for　the　performance　and　yield　optimization　of　devices　by　quality　assessment　of　2D　semiconductors　prior　to　device　fabrication.　©　2021　American　Chemical　Society.