Abstract: In the paper, an inhomogeneous isoparametric finite element method is employed to investigate an interfacial crack between the gradient coatings and homogeneous substrate, as well as that of bimaterials for comparison. It turns out that the stress intensity factors (SIFs) can be effectively reduced in the gradient coatings than in bimaterials. In addition, the influences of coatings' thickness and gradient parameter on the SIFs are also studied in detail. The results indicate that when the thickness of coatings is greater or equal to the length of crack, the SIFs are insensitive to the variation of coatings' thickness. Concerning the influence of the gradient parameter, for the power index m > 1, the SIF K_Ⅱ, which is very small as compared to K_I, keeps virtually unchanged with variation of m, and the field near the crack-tip is similar to that of homogeneous materials. Whereas for < 1, the SIF K_Ⅱ is sharply increased with the decrease of m, and the crack-tip field is obviously governed by K_I and K_Ⅱ, suggesting that the fracture is mixed mode.