Abstract: In order to test aspheric surfaces with high accuracy, the concept of virtual glass is adopted and computer generated hologram is designed.Glass model whose index equaled to zero was established using ZEMAX.It can make the construction wave-front of CGH impinge along the normal direction of aspheric surface, simplify the design and optimization process of compensator and improve the accuracy of design.The maximum optical path difference is less than 0.000?7?λ(λ=632.8?nm).Meanwhile, the program computing technological parameters of CGH is made.The radial coordinate of every ring, the minimum feature size, the maximum number of rings are given, figure of phase, continuous surface and stair surface were listed using this program.It provided effective solution path for optical design and actual fabrication.