Abstract: The technology of beam combination is an effective method to obtain high power and quality beams.Aiming at the demand of high power beams in the device of ICF in the future,an isosceles triangle phase grating was designed.Simulated and analyzed results indicated that the combination efficiency of four incident beams reached 90.2%,which was 22% higher than the efficiency of Dammann phase grating.Besides,the processing of the isosceles triangle phase grating was not difficult.So it is important and practical perspective in the future.