The macro properties of material depend on the microstructure features which are the result of a variety of microscopic mechanism under the action of external fields. So the non-destructive in situ investigation of the microstructure evolution process is an effective approach to research these mechanisms. The synchrotron radiation computer tomography technique is a latest non-destructive testing technique which can realize the 3-D and on-line observation of internal microstructure of materials under extreme condition (e.g. high temperature, intense radiation). In our group, SR-CT technique has been applied to carry out the in-situ investigation of microstructure evolution of materials under external fields, such as in the area of sintering and mechanics. Especially in the area of sintering, we have made experimental validation, evaluation and further explore on conventional and microwave sintering theory, and some qualitative and quantitative results were given in our research.