Abstract: As a new kind of advanced composites, functionally graded material combines various properties of its constituents. At the same time, the continuous variation of properties yields some excellent mechanical advantages. In this paper, based on a beam model, the thermal stresses and the fracture parameters of crack parallel to the interface between a FGM/substrate material and a mutil-layer material are analyzed. The buckling-driven delamination of functionally graded film is investigated too. It is shown that the FGM can effectively alleviate the stress concentration in the interface and its effects on micro defects, and improve materials strength and toughness inccodinately.