EFTEM has become a very useful tool in characterizing material properties, because it allows studying local chemical and electronic properties of a specimen with nanometer level spatial resolution. There are two spectroscopic imaging methods have been established to obtain both the spatial and the spectra information, I (x, y, ΔE), which can be quantitatively evaluated. One technique, as known as spectrum-image method, is based on scanning the electron beam across the sample to acquire the EELS spectrum with two-dimensional information. Conversely, the other method retrieves the spectra in a specific position from a series of energy loss images, as known as imaging-spectrum method. The spectrum-image method can be achieved with better energy resolution, however, a long acquisition time. Compared to spectrum-image method, which acquires a series of spectrum with scanning probe, the advantage of imaging-spectrum method is the capability of simultaneously recording abundant information in a series of maps.