By analyzing the casting defects in aluminum alloy blade, it is pointed out that the casting defects are closely relative to pouring position, gating system design, exhaust of the mold house and the mold filling temperature. Based on the mentioned analysis, some improvment methods, including mold tilt, horizontal pouring and vertical cooling, design of exhaust gutter along the parting surface, changing in thickness of coating layer and adjustment of solidification sequence,are presented.