Abstract: Thermal conductivites of fibrous refractories at high temperature were investigated in this paper based on microstructure analysis with fractal theory.It was found that the fractal dimension and volume fraction of fiber material are two important parameters affecting heat conduction.According to the equivalent heat resistances,a model of heat transfer inside the fiber material was developed for prediction of effective conductivities of the material at high temperature.Model predicting are in good agreement with experimental data as well as with results from literature.