The　heterogeneous　single-atom　nanomaterials　(HSANs)　are　being　increasingly　embodied　in　the　field　of　sensors　due　to　their　excellent　performance　on　improving　sensitivity　based　on　the　active　centers　formed　by　the　metal-support　interaction　and　the　high　metal　utilization　efficiency.　In　this　review,　we　comprehensively　summarize　the　metal-support　interactions　during　the　process　of　HSANs　construction,　including　the　interactions　between　metal　single-atom　and　laminar　carbon-based　nanomaterials,　MOFs/MOFs-derived　nanomaterials,　metal　oxidation/sulfide　nanomaterials,　and　metal　nanomaterials.　These　metal-support　interactions　contribute　to　the　functional　characteristics　of　HSANs　due　to　the　adjustable　active　centers　such　as　M-Nx,　M-Ox,　and　M-Sx,　which　lay　good　foundation　for　sensor　applications.　Then,　the　sensors　based　on　electrocatalysis,　photocatalysis,　catalytic　colorimetry,　photoelectrochemistry　and　the　synergetic　sensing　of　active　centers　in　HSANs　are　summarized.　The　well-defined　active　centers　constructed　by　the　metal-support　interaction　are　also　highlighted　to　elucidate　the　functional　mechanism　and　structure-activity　relationship　in　sensors.　Finally,　challenges　and　opportunities　on　further　applications　of　HSANs　in　sensors　are　put　forward.