Abstract: With the advantages of high sensitivity and simple operation, the nano-indentation technology can be used to obtained micro-and nano-size mechanical properties of block materials, films, coatings and so on. Especially with the advancement of material genome technology, it is more and more widely used to characterize mechanical properties. In this paper, the Oliver-Pharr principle and the application of nano-indentation in the load-displacement, hardness, elastic modulus, fracture toughness, creep properties, residual stress and interfacial characterization are introduced. Some existing problems of the nano-indentation technology are analyzed:The mechanical property parameters testing by nano-indentation technology should take into account the applicability of the test model; In order to minimize or even eliminate the effect of the surface state and physical characteristics of material on the accuracy and repeatability of the test results, the processing of material surface requires high technology and consistency; The nano-indentation test has poor repeatability, because of the difficulty in accurately locating the test position, the size deviation of the standard indenter and the thermal drift of the device itself.