Aluminum nitride (AlN) is one of the most popular piezoelectric materials for high frequency resonators, filters and sensors. The piezoelectric property, i.e. electromechanical coupling coefficient, of AlN thin film is highly related to its crystalline orientation. AlN thin films with various c-axis-tilted angles can be fabricated by the RF sputtering technique. The crystallization and grain growth orientations of AlN thin film are examined by XRD, SEM, and TEM, while the bonding condition and nano-mechanical properties are investigated by a raman system and a nano-indentation technique.