Electron backscatter diffraction (EBSD) based on scanning electron microscopy (SEM) is a powerful technique to automatically and quantitatively measure the grain/subgrain size, local texture, point-to-point orientations, strain and phase identification [14]. With the help of field emission SEM (FESEM), high resolution EBSD can investigate the grains/subgrains as small as a few tens of nanometers [4] with a good angular resolution (~0.5°) [5]. It has been established that EBSD has a lot of advantages over transmission electron microscopy (TEM), such as simple sample preparation, automatic scanning and indexing, ultra-fast speed, large area investigation and a lot of post- processing results derived from one EBSD scan. After two important steps of development [4], the EBSD speed has increased gradually with the fast development of camera technique. It has increased sharply up to 1100 patterns per second (PPS) by adopting the offline EBSD techniques (Fig. 1). Therefore, the number of published articles related to EBSD has been increasing sharply year by year (Fig. 2, data are searched from www.scopus.com). In recent years, severe plastic deformation (SPD) [6], e.g. equal channel angular pressing (ECAP), high pressure torsion (HPT), cyclic extrusion compression (CEC) and accumulative roll bonding (ARB), has been increasingly used in processing ultrafine grained (UFG, grain size in the range 1001000 nm) or nanostructured (≤100 nm) materials directly from bulk samples. SPD techniques can easily reach an equivalent strains ≥10, which in turn leads to an equiaxed microstructure with a high density of grain boundaries (high angle grain boundaries (HAGBs) ≥60%). In order to understand the grain refining mechanism induced by SPD and to control the microstructure evolution, EBSD is very important to be employed, especially increasing demand for in situ heating and tension, and 3D EBSD investigation. EBSD patterns are generated by backscatter diffraction of a stationary beam of high-energy electrons from a volume of crystal material within 50 nm depth in