Nanoindentation techniques are widely used for the study of nanomechanical properties of thin nanocomposite coatings. Theoretical concepts and practical use of nanoindentation method are summarized with reporting the applications of these tests in characterization of some particular thin nanocomposite hybrid coatings prepared by sol-gel process. The better mechanical properties can be obtained in the investigated hybrid coatings in compare with the pristine polymer coatings. It is demonstrated that the adding nano inorganic fillers can be influenced on physical-mechanical properties of coatings as well their microstructures. However, the adhesion of nanocomposite coatings is dependent on the chemical bond in the interface, microporous and defects in the network. Coating can be delaminated on exposure to extreme UV and humidity conditions. The mechanism of coating's failure as well microstructural changes can be studied by nanoindentation technique in statistic or dynamic modes.