Aluminum foam as porous material in wide use has the excellent mechanical and thermal properties. As adhesive process technique is used by bonding such composites as aluminum foam, fracture toughness at adhesive joint is the main point to investigate. In this study, DCB specimens are manufactured to evaluate the strengths at adhesive joints on the basis of British industrial and ISO international standards. Four kinds of specimens are made by changing the height of the specimen and these experimental results are compared with each other. Energy release rates are also calculated at mode I. As the hight of specimen becomes higher, reaction force and energy release rates become higher. Through the correlation obtained by this study result, aluminum foam material bonded with adhesive can be applied to the real composite structure and mechanical property and fracture toughness are analyzed systematically.