The results that modification on LY12 aluminum alloy surface by high current pulse electron beam (HCPEB)indicate that there are many pits on LY12 aluminum alloy surface, the number of melting pit decrease and the diameter get bigger with the time of irradiation increasing. According to XRD analysis, some phrase such as α-Al,CuMgAl2 and CuAl2 are found in the melted layer treated by HCPEB and the melted layer recrystallization have preferred orientation. The result of electrochemical corrosion experiment show that the LY12 samples after treatment have better corrosion resistance than the matrix, corrosion potential increases from - 626.92mV to - 523.33mV and corrosion current decreases from 1.09×10-7 A to 3.12×10-9 A, corrosion resistance is improved obviously.