A novel method with a single gradient index (GRIN) lens for 1×N fiber coupling is proposed. A calculation and design method is founded to calculate beam focus position when a pointolite is illuminating an angular surface of a GRIN lens. In coupling module, the GRIN lens has one polyhedral end which is taken as the input port to split input light into several beams, and split beams get focused through GRIN lens. Beam focus position can be adjusted by some system parameters. These beams get focused through the GRIN lens, and couple into output fibers and fiber cores separately, meanwhile aberration is corrected. The simulation results show that the coupling models in different applying situations have high coupling efficiency by optimizing some key parameters, e.g. tilt angle of surfaces and object distance. It can be proved that the coupling method is simple in structure and easy to assemble. It provides a practical coupling method for variety of photonic crystal fibers, multi-core fibers, fiber bundle and fiber combining.