Laser decoy jamming is an effective countermeasure for semi-active laser guided weapon.Diffuse reflection board used as the false target is one of standard parts in laser decoy jamming.In order to improve decoy effect of diffuse reflection board during laser jamming,the layout of the diffuse reflection board is researched.According to the threatening information of semi-active laser guiding and the reflective characteristic of diffuse reflection board,the concrete layout of the diffuse reflection board including its position,reflection orientation,and number of reflection boards are analyzed.The quantitative restriction expressions are further provided.The research provides an theoretical reference for diffuse reflection board layout for field test.