Abstract: The relationship between fractal dimension of the 08Al steel plate blast sanded surface that of the steel-aluminium solid to liquid bonding plate shearing surface and interfacial shear strength was determined by using fractal theory.It was recieved that the maximum interfacial shear strength 65.3 MPa corresponded to the optimum fractal dimension 2.33 of the shearing surface of bonding plate,and the fractal dimension of the blast sanded surface of Steel plate Which was blast sanded by the wheel made by steel wire (diameter was 1.4mm) was 2.36.