Grin fiber lens is used in achieving the effective coupling between laser diode (LD) and single mode fibers (SMFs). The ABCD matrix theory of the all-fiber coupling of LDs is also consummated. During the experiment, the optimized length of the Grin fiber is precisely accomplished through a home-made fiber-progressing system to achieve a high coupling efficiency according to the focusing characteristic of Grin fiber, and the maximum efficiency of 80.5% is ultimately realized. This all-fiber coupling configuration has several advantages including the small-sized, easy-made and low cost, which is important for the realization of the low-cost, pigtailed LDs.