The fracture characterizations on mixed-mode crack of functionally graded materials (FGMs) are investigated using digital speckle correlation method (DSCM). The stress intensity factors at mixed-mode crack tip are obtained from digital speckle displacements fields. In combination with finite elements simulation results, the influences of gradient coefficients on fracture behavior of mixed-mode cracks are analyzed. All the results show that the influence of gradient coefficients on fracture modes is not noticeable, and the stress intensity factor at the crack tip in graded materials are clearly influenced by the gradient coefficients, i.e., the stress intensity factors decrease with the increasing of gradient coefficients. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 123: 2467-2475, 2012