SAF2906　duplex　stainless　steel　was　nitrided　at　610℃　for　60,　90,　120,　150　and　180　min,　respectively,　then　followed　by　the　same　post-oxidation　process　with　heating　temperature　at　400℃　for　30　min.　The　microstructure　and　wear　resistance　of　the　treated　samples　were　investigated　by　means　of　OM　(optical　microscope),　SEM　(scanning　electron　microscopy),　XRD　(X-ray　diffraction),　microhardness　test　and　wear　resistance　test.　Microstructure　observation　indicates　that　the　surface　layer　of　the　samples　after　QPQ　treatment　is　composed　of　oxide　layer,　compound　layer　and　diffusion　layer　from　the　surface　to　the　center.　The　oxide　layer　is　composed　of　Fe3O4.　The　main　phase　of　the　nitrided　layer,　such　as　compound　layer　and　diffusion　layer,　consists　of　CrN,　α-N,　Fe2-3　N　and　S　phase.　With　nitriding　time　increase,　the　growth　rate　of　the　compound　layer　is　gradually　slowed　down,　and　the　loose　microstructure　exhibits　more　serious.　Porosity　of　the　surface　layer　is　increased　with　the　extension　of　time,　and　its　relative　density　is　declined.　The　surface　hardness　of　QPQ　treated　samples　is　3　times　more　than　the　substrate,　which　is　first　increased　and　then　decreased　with　increasing　in　nitriding　temperature,　and　the　optimum　hardness　is　1164　HV0.2　at　120　min.　The　dry　sliding　results　show　that　the　wear　resistance　of　QPQ　treated　samples　reaches　at　least　20　times　than　that　of　the　substrate,　and　the　desirable　wear　resistance　is　presented　at　120　min.　The　worn　surface　morphology　observation　reveals　that　the　abrasion　form　of　the　substrate　belongs　to　plough　cutting,　while　the　abrasion　form　of　QPQ　treated　samples　belongs　to　micro-cutting.