The fractal characteristics of concrete materials microstructure are analyzed with fractal theory. The fractal dimension of concrete materials microstructure in the different conditions are tested and counted by code and box Dimension. The result shows that the fractal characteristics of concrete materials microstructures are highly notable, as interface of cement clinker mineral, dispersed state of unhydrated cement particles, crack of hardened cement paste, hydration product and pore structure of hydrated cement paste section. Proving it is effective to measure surface of cement clinker mineral, figures of hydration C-S-H grains and outlines, pore structure of concrete section. Using box dimension is effective to test microcracks and pore structure of section of motor samples and fiber-hydrate. In the course of fractal analysis, the dimensions of fractal are bigger than their topologic dimension, and they are smaller than their space dimension, they are keeping with the fractal theory.