Anodic alumina has exhibits a homogeneous morphology of parallel pores that can be easily controlled between 10 and 400 nm. AAO(Anodic Aluminum Oxide) structure is the transversely isotropic material due to the parallel pores. In this study, mechanical properties of the AAO structures are measured using the nano-indentation method. Nano-indentation technique is one of the most effective methods to measure mechanical properties of nano-structures. Investigation of mechanical properties, such as the indentation modulus and hardness of the AAO structure with varying nano-pore sizes, was performed using the nano-indentation method. The results showed that the indentation modulus and hardness decreases monotically as the pore size increases.