The surface modification of magnesium alloys (AZ31 and AZ91HP) was studied by a high current pulsed elect ron beam( HCPEB) . The result s show that the cross2sectional microhardness of t reated samples increases not only in the heat affected zone ( HAZ) , but also beyond HAZ , reaching over 250μm. This is due to the action of quasi2static thermal st ress and the shock thermal st ress wave with materials , which result in it s fast deformation on the surface layer and so increases microhardness. For the AZ91HP alloy , a nearly complete dissolution of the inter2 metallic phase Mg17Al12 is observed , and a super2saturated solid solution forms on the re2melted surface , which is due to the solute t rapping effect during the fast solidification process. Measurement s on sliding wear show that wear resistance is improved by approximately 5. 6 and 2. 4 times for the AZ31 and AZ91HP respectively , as compared with as2received samples.