Abstract: Residual stress is a key factor affecting the service performance and processing performance of metal materials, and its accurate measurement has important theoretical significance and engineering value. The crack flexibility method monitors the change of strain response by introducing prefabricated cracks, and combines the theory of elastic mechanics and finite element analysis method to invert the distribution of residual stress field, which has the characteristics of high precision and wide applicability. The theoretical basis, test process and finite element calculation method of measuring residual stress by crack flexibility method are systematically expounded, and the key error factors affecting the measurement accuracy are analyzed in depth. The typical application cases of metal sheet and additive manufacturing parts are introduced, and the technical advantages of this method in metal rolling sheet and laser deposition components are discussed. The systematic analysis of the theoretical method and engineering application of crack flexibility method can provide an important reference for expanding the application of this method in the field of advanced manufacturing.