The coupling application of tapered optical fiber and semiconductor laser has great practical value. The beam shaping effect of the tapered area is analyzed based on the principle of geometrical optics. The coupling model of the semiconductor laser and the tapered fiber is built with ZEMAX. The influence of the coupling efficiency caused by the different working distance between the source and the tapered fiber tip, and the variation of the end diameter of the tapered fiber are explored. The results are researched by the practical experiment.