Two-dimensional　layered　transition　metal　dichalcogenides　(TMDCs)　have　demonstrated　a　huge　potential　in　the　broad　fields　of　optoelectronic　devices,　logic　electronics,　electronic　integration,　as　well　as　neural　networks.　To　take　full　advantage　of　TMDC　characteristics　and　efficiently　design　the　device　structures,　one　of　the　most　key　processes　is　to　control　their　p-In-type　modulation.　In　this　review,　we　summarize　the　p-/n-type　modulation　of　TMDCs　based　on　diverse　strategies　consisting　of　intrinsic　defect　tailoring,　substitutional　doping,　surface　charge　transfer,　chemical　intercalation,　electrostatic　modulation,　and　dielectric　interface　engineering.　The　modulation　mechanisms　and　comparisons　of　these　strategies　are　analyzed　together　with　a　discussion　of　their　corresponding　device　applications　in　electronics　and　optoelectronics.　Finally,　challenges　and　outlooks　for　p-/n-type　modulation　of　TMDCs　are　presented　to　provide　references　for　future　studies.