The influence of changing design parameters on diffractive microlens is investigated . the effects of changing design focal length and microlens material refractive index on diffractive efficiency and airy diffraction disc radius are presented . the numerical results are discussed by qualitative analysis 首先研究了设计参数变化对衍射微透镜的影响,给出了设计焦距和透镜材料折射率变化对衍射微透镜衍射效率、爱里斑半径等的影响,并对分析结果作了定性讨论。