Great strides have been made over the past two decades in the development of techniques for studying the mechanical properties of materials on the micron and submicron levels. In this review paper, first, several definitions, classifications and their scopes used for hardness are introduced. Secondly, developments for nanoindentation techniques are summarized, especially the measuring principles of nanoindentation, CSM(Continuous Stiffness Measurement), high resolution load/displacement sensors, several typical tips, sample preparation, reference to the point of contact, experimental methods, instrument calibration and so on. With nanoindentation systems, quantitative data can be obtained: hardness, elastic modulus, fracture toughness, storage and loss modulus, stress exponent. Finally, advances in nanoscratch techniques are briefly discussed.