Analytical model based on the Bernoulli beam theory and fracture mechanics have been developed to predict the fracture toughness of a tri-layered beam with interfacial crack. In this work, a double cantilever beam test is conducted to determine the fracture toughness of mode I. The strain energy release rate for the double cantilever beam is expressed as a function of the material properties and thickness of the tri-layer beam. The analytical solution is validated with the finite element result. Good agreement demonstrates that the proposed approach is able to provide an efficient way for the calculation of the fracture toughness of a multi-layered structure. The effects of material properties and thickness between the adjacent layers of the interfacial crack are examined through a parametric study.