The　out-of-plane　mirror-symmetry　breaking　in　Janus　transition　metal　dichalcogenides(J-TMDs)　and　their　van　der　Waals　heterostructures　(vdW　HSs)　induces　intrinsic　Rashba　splitting,　which　could　offer　the　possibility　to　revolutionize　spintronic　devices.　However,　there　is　some　controversy　about　the　fundamental　reason　of　Rashba　splitting　changes　under　different　manipulation　methods.　This　study　investigates　the　Rashba　splitting　in　AA-stacking　Janus　PtSeTe/Se2Te　vdW　HS　with　a　Te　−　Te　interface　by　first-principles　calculations,　as　well　as　the　manipulation　of　Rashba　splitting　through　charge　doping　and　in-plane　biaxial　strain.　The　interlayer　distance　exhibits　an　inverse　relationship　with　biaxial　strain,　while　the　potential　profile　of　the　HS　remains　almost　same.　Consequently,　it　can　be　inferred　that　the　intrinsic　electric　field　is　influenced　by　the　interlayer　distance　under　biaxial　strain.　Thus,　the　underlying　physical　mechanism　responsible　for　the　changes　in　Rashba　splitting　due　to　biaxial　strain　is　attributed　to　the　variation　in　interlayer　distance.　The　Rashba　splitting　shows　a　linear　variation　within　the　charge　doping　range　of　−0.5e　to　0.3e,　while　it　demonstrates　a　nonlinear　variation　in　the　range　of　0.3e　to　0.5e,　which　may　be　related　to　the　electronegativity　reversal　of　the　PtSeTe　layer　at　0.3e　charge　doping.　These　results　enrich　the　fundamental　understanding　of　the　Rashba　effect　in　Janus　HS.　©　2024　Elsevier　B.V.