The effect of the grain orientation on corrosion behavior of rolled AZ31 magnesium alloy is investigated in this study.The test samples have a similar surface roughness to the Mg alloy in practical application.The immersion test and electrochemical impedance spectroscopy show that the TD-ND planes dominated by(1010),(1120) and(1011) oriented grains show a higher corrosion resistance compared with these of the RD-TD planes which consist mainly of(0001)oriented grains.Here,RD,ND and TD represent the rolling direction,the normal direction and the transverse direction of the alloy sheet,respectively.The surface morphologies of the alloys at various immersion stages are observed by scanning electron microscopy,and the surface topography of the alloy substitutes is also observed by laser scanning confocal microscopy.The TD-ND planes show a regular corrosion along the TD direction,but the RD-TD plane shows an irregular corrosion. The effect of the grain orientation on corrosion behavior of rolled AZ31 magnesium alloy is investigated in this study. The test samples have a similar surface roughness to the Mg alloy in practical application. The immersion test and electrochemical impedance spectroscopy show that the TD-ND planes dominated by (1010), (1120) and (1011) oriented grains show a higher corrosion resistance compared with these RD-TD planes which consist mainly of (0001) oriented grains. Here, RD, ND and TD represent the rolling direction , the normal direction and the transverse direction of the alloy sheet, respectively. The surface morphologies of the alloys at various immersion stages are observed by scanning electron microscopy, and the surface topography of the alloy substitutes is also observed by laser scanning confocal microscopy. TD-ND planes show a regular corrosion along the TD direction, but the RD-TD plane shows an irregular corrosion.