Abstract: With the use of the theory of blazed phase gratings,the color separation phase grating used for ICF drivers is designed,which can off-axis separate the fundamental,2nd and 3rd harmonic waves.Theoretically,its diffraction efficiency for 0'th order at the 3rd harmonic wave is 100%.Experimentally,a color separation grating is made.Both its separation angles (at the 1st and 2nd harmonic waves) and its diffraction efficiencies for 0'th order are measured,and some significant results are presented.