This investigation comprehensively examines the nano-mechanical properties of AlTaO4 for the first time, including Young's modulus (E), hardness (H), and fracture toughness (KIC). Variability in the regional distribution of E and H within AlTaO4 is elucidated through an examination spanning both the grain and bulk material scales, and offers a correlational equation of E and H from fit statistical outcomes. Additionally, the H/E ratio and micro-hardness dissipation parameter of AlTaO4 reach 0.063 and 0.61, respectively, which demonstrate its exceptional wear resistance. Further investigation emphasizes that the distinctive crystalline structure, short bond lengths, high bond strength, and elevated charge density around aluminum ions significantly contribute to the high E (208 GPa) and H (13.1 GPa) of AlTaO4. The capacity for energy absorption during elastic deformation enhances crack formation energy and contributes to the relatively high fracture toughness (2.6 MPa m1/2) of AlTaO4. This work elucidates the excellent mechanical properties of AlTaO4 by applying nanoindentation and first-principle calculation, which will advance the applications of AlTaO4 as high-temperature materials.