Abstract: Aim to investigate the thermal stress for the interface of functionally gra- dient material (FGM). Methods Based on thermoelastic assumption, the design and structure optimization of functionally gradient material were first fulfilled by use of fi-nite element method, and the thermal stress on the matrix-particulate interfaceof the fabricated functionally gradient materials were calculated using double-layer-embedment model. Results The mutating stresses on the both sides of the matrix-particulate interface in the graded layer were obtained, and the stress and the volume fraction of materials in every graded layer were different. Conclusion The ultimatemutation of matrix-particulate interface stress causes the matrix-particulate interfacecrack to be initiated.