A telescope fiber coupling system using aspheric lens for coupling freespace optical field into singlemode fiber in allfiber lidar is devised. Its layout is designed and optimized for coupling efficiency into singlemode fiber through ZEMAX software. Moreover, the preliminary experiments are carried out using the LED and laser as optical source, and then the coupling efficiencies of directive coupling and aspheric lens coupling are compared. Experimental results show that the coupling efficiency using aspheric lens for multimode optical source may be increased by 47% than that of directive coupling, which is close to simulating result of 45%, and that the ratio of coupling optical power for different fibers is roughly close to the square of the corediameter ratio. Furthermore, it is shown that the coupling efficiency of this way for singlemode optical source may be raised by 20%, and that the ratio of coupling optical power is approximately 2.4 times more than the square of its corediameter ratio, which is significant to establish the allfiber rotational Raman lidar.