Interface is significant part in the structure of composite materials. However, crack and fracture are often happened in the
interface and deprive the whole mechanical functions of composite materials. In order to obtain the fracture mechanism
of materials with interface, different defect shape in interface and different layer ratio for metal-porcelain bimaterial are
studied by electronic speckle pattern interferometry (ESPI). The experiment results indicate that the resisting fracture
capacity for the specimen with vertical interface crack is quite weak. But the mechanical behavior of specimens with no
defect in interface has sufficient capacity resisting fracture. Simultaneously, the process of experiment shows that ESPI is
suitable for measuring small displacement.