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In order to improve surface properties,High chromium austenitic base heat-resistant cast steel was scanned with a 5 kW continuous wave CO2 laser,the specimen was aged at the temperature of 600 ℃~900 ℃.The microstructura and phase composition of the specimen were analysed with optical microscopy,X-ray diffractionse and electronic microscope.The hardness and the property of high temperature abrasion were measured.The results show that as cast structure of high chromium cast steel is coarsely and non-homogeneous,is mainly austenite,ledeburite and carbides.After laser remelting,the section is divided into remelted zone consisted of austenite and carbides,quenched zone composed of austenite and carbides,transition zone and base metal.The region and the hardness of various zones are related to the laser processing parameters.The hardening depth of melted zone and quenched zone may be up to 150 μm~300 μm.after aging the microstructure of steel consists of austenitic base,dispersed carbides M6C and metallic compound laves phase.The alloy with new coating of laser heat treatment and aging has superior high temperature abrasion properties and oxidation resistance.