Abstract: The mechanical properties of nano-Al2O3coating on Al2O3short fiber reinforced epoxy composites were analyzed with nano-indentation and nano-scratch tests to study the relationship between the properties and coatings and coating procedures. The procedures to coat the coatingsduring and after the solidification of the epoxywere used. The former and latter proceduresmake the elastic modulus of the coatings increase from 1. 0 GPa for thematrix to 3. 3~3. 9 GPa and 2. 1~4. 0 GPa, respectively, and the hardness of the coatings raise from 200MPa for thematrix to 700~1 300MPa and 400~600MPa, respectively.