Abstract: The tensile shear strength of metal/adhesive interface was tested in a tensile-shear test after metal substrates with different surface roughness were bonded by adhesive. The effect of adsorption, diffusion, mechanical resistance and notch effect on tensile shear strength in different ranges of roughness was explained by adhensive tribological models of microscopic interface and microscopic observation. The results show that when surface roughness of metal was small enough, adsorption and diffusion were main influence factors, the tensile shear strength of the mental/adhesive interface decreased rapidly with the increase of surface roughness of metal. Then the mechanical resistance played a major role as surface roughness of metal increased, so the tensile shear strength of interface increased with it until to about 8 MPa then decreased slowly because of increasingly obvious gap effect.