The　nanoplasmonic　sensor　of　the　nanograting　array　has　a　remarkable　ability　in　label-free　and　rapid　biological　detection.　The　integration　of　the　nanograting　array　with　the　standard　vertical-cavity　surface-emitting　lasers　(VCSEL)　platform　can　achieve　a　compact　and　powerful　solution　to　provide　on-chip　light　sources　for　biosensing　applications.　Here,　a　high　sensitivity　and　label-free　integrated　VCSELs　sensor　was　developed　as　a　suitable　analysis　technique　for　COVID-19　specific　receptor　binding　domain　(RBD)　protein.　The　gold　nanograting　array　is　integrated　on　VCSELs　to　realize　the　integrated　microfluidic　plasmonic　biosensor　of　on-chip　biosensing.　The　850　nm　VCSELs　are　used　as　a　light　source　to　excite　the　localized　surface　plasmon　resonance　(LSPR)　effect　of　the　gold　nanograting　array　to　detect　the　concentration　of　attachments.　The　refractive　index　sensitivity　of　the　sensor　is　2.99　×　106　nW/RIU.　The　aptamer　of　RBD　was　modified　on　the　surface　of　the　gold　nanograting　to　detect　the　RBD　protein　successfully.　The　biosensor　has　high　sensitivity　and　a　wide　detection　range　of　0.50　ng/mL　–　50　µg/mL.　This　VCSELs　biosensor　provides　an　integrated,　portable,　and　miniaturized　idea　for　biomarker　detection.　©　2023　Optica　Publishing　Group　under　the　terms　of　the　Optica　Open　Access　Publishing　Agreement.