To identify the aircraft carrier in high resolution remote sensing visible light image,an method based on least inertia axis is proposed.The concepts of area and length sequence features of the ship targets are presented and explained,and both of them can be obtained by least inertia axis.Their similarity transformation invariance is proved and applied in aircraft carrier identification.Experiment results show that the area and length sequence features have good similarity transformation invariance.The outlines and region of ship targets can be well characterized by them.The aircraft carrier target can be precisely separated from the ship targets.The method has high correct identification rate.