The axicon line focusing and convex lens imaging systems are analyzed and the ef fect on their imaging system′s focal depth is explored via the Fourier optics t heory and the lens imaging theory.The optical design software of ZEMAX is used to stimulate the cross-sect ion optical intensity distributions of the system at different axial distances.Taking the blue LED as the light source in the experiment,these two imaging systems are verified and the cross-sec tion optical intensity distributions at different axial distance are photographed .Results show that th e line focusing characteristics of axicon can focus light continuously to the points along the axis,and that the resolution of images is higher.It is no need to adjust focus within the maximum non-distract ion distance,and the focal depth is larger.The theretical analysis,numerical simulation and experimental results a re consistent.