Abstract: 25Cr5MoA/Q235 steel clad plates were prepared with the composite slabs heated to the temperature between 800℃ and 1 100℃, held at each temperature for 30 min, rolled one pass and reduced from 50% to 70%. Their bonding shear strengths were tested by the electron universal testing machine CMT4105 and the metallographic microstructures of their interfaces were observed by optical microscope and SEM. The results show that the rolling temperature between 900℃ and 1000℃ is favorable to the bonding of the steels and pass reduction is crucial to the bonding strength. When the pass reduction becomes large, cleaner and more activated new interfaces will be obtained and the grains will The gradient metallographic changes of grains can be refined, as a result the bonding strength can be enhanced. also raise the bonding strength of the clad plates.