The physical mechanism of material microstructure evolution is essential in developing the right properties for the designer of material forming process. However, many investigation results have shown that the microstructure evolution only focused on using X-ray diffraction (XRD), differential thermal analysis (DTA) and scanning electron microscope (SEM) approach. There were still few experimental and computational researches paid attention to the analysis of material microstructure evolution based on microstructure image characteristics. In this paper, the physical mechanism of material microstructure evolution based on Bi-dimensional empirical mode decomposition (BEMD) and image multi-scale entropy (MSE) during heat-treatment process is proposed, using glass-ceramic material as an example. The experimental results show that the evolution process of the microstructure images can be depicted quantitatively, in turn, it also confirms that the complexity of image information was changed by the distribution of grain size and glass phase composition.