The single-lens coupling system was analyzed.The relationship between the coupling efficiency and the position of the lens is calculated when focal length of the lens is 103.26 mm,and the relationship between the coupling efficiency and the focal length of the lens is calculated when the distance between the lens and the end of fiber is 120 mm.The coupling experiment was conducted by using single-lens coupling system,and the seed in the experiment is a 1030 nm SESAM mode-locked solid-state laser(M2≤1.2) and the diameter of ROD-PCF core is 85 μm(DMF=65 μm).Finally,the measured coupling efficiency is about 35%~42%.Because the doped Yb3+ ions in the fiber has a certain absorption effect on the 1030 nm laser,the actual coupling efficiency should be greater than the measured value.