Abstract: By means of caustic method combined with image holo-photoelasticity method, the accuracy of Stress Intensity Factors(SIFs) of mixed-mode crack is efficaciously improved.This paper describes the principles, procedures and technique of this combined method.With this method, the problems of kinked cracks concerned in engineering are investigated.Expritnetital results show that it is proper to replace the kinked crack with its corresponding;inclined crack for caleulating its SIFs.