Herein,　shot　peening　(SP)　using　different　parameters　is　performed　on　4Cr9Si2　martensite　engine　valve　steel　at　elevated　temperatures.　The　microstructure　of　the　modified　layer　is　characterized　via　optical　microscopy　(OM),　transmission　electron　microscopy　(TEM),　and　X-ray　diffraction　(XRD).　High-temperature　wear　tests　are　performed　under　dry　sliding　conditions　at　450　°C　using　a　pin-on-disc　wear　tester,　and　the　worn　surface　is　evaluated　via　scanning　electron　microscopy　(SEM)　and　energy-dispersive　spectroscopy　(EDS).　The　results　show　that　SP　refines　the　grains　on　the　top　surface　to　19.8　nm　and　yields　numerous　dislocations.　Meanwhile,　the　compressive　residual　stress　and　microhardness　of　the　treated　surface　increase　to　−575　MPa　and　486.33　HV0.2,　respectively.　At　elevated　temperatures,　the　increase　in　hardness　provides　resistance　to　plastic　deformation　and　improves　the　performance　of　the　oxide　film.　Compared　with　an　untreated　sample,　sample　SP4　shows　a　65.23%　decrease　in　wear　rate　and　its　wear　resistance　improves　significantly　at　elevated　temperatures.　In　addition,　the　wear　mechanisms　of　SP-treated　samples　are　primarily　oxidation　wear　and　delamination.　©　2021　Wiley-VCH　GmbH