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 首先研究了設計參數變化對衍射微透鏡的影響,給出了設計焦距和透鏡材料折射率變化對衍射微透鏡衍射效率、愛里斑半徑等的影響,并對分析結果作了定性討論。