We　are　concerned　with　the　time-asymptotic　stability　of　planar　rarefaction　wave　to　a　non-conservative　two-phase　flow　system　described　by　two-dimentional　compressible　Euler　and　Navier-Stokes　equations　through　drag　force.　In　this　paper,　we　show　the　planar　rarefaction　wave　to　a　non-conservative　compressible　two-phase　model　is　asymptotically　stable　under　small　initial　perturbation　in　H-3.　The　main　difficulties　overcome　in　this　paper　come　from　the　non-viscosity　of　one　fluid　and　the　interaction　between　two　fluids　caused　by　drag　force.　The　stability　result　is　proved　by　the　energy　method.