Our main research direction is using X-ray imaging technique to study the physical properties of granular materials. Granular materials exist in a wide range of natural phenomena closely related to human beings, including earthquakes and deserts. It is also closely related to various human activities, including soil, ore and so on. Granular materials have many important applications in fields like civil engineering, chemical engineering and geology. The current granular theories are mainly based on empirical constitutive models, and has encountered many difficulties in practical applications. Since granular material is by nature out-of-equilibrium, the liquid-solid phase transition happens through glass/jamming transition, so its property is very different from that of the equilibrium Newtonian fluid and crystalline solid. We use X-ray imaging technique to study the microstructure and dynamics of granular materials, in order to establish a statistical mechanics framework for granular matter, to understand the liquid-solid phase transition behaviors, and to establish the corresponding continuum mechanics. Two of the 125 most important unsolved scientific questions listed in 2005 by Science magazine: "can we develop a general dynamic theory of turbulence and granular flow?" and "what is the nature of non-crystalline material?" are directly related to this.The results also have implications for metallic glass, traffic jam and the mechanism of cancer metastasis.