Abstract A method based on the uptapering of photonic crystal fiber for low-loss coupling between photonic crystal fibers and single-mode fibers is presented. The impacts of uptapering ratio on coupling loss are investigated by beam propagation method. The results show that this method can greatly reduce the coupling loss between the two types of fiber. Besides, this method is available for the coupling between a variety of photonic crystal fibers and single mode fibers, especially for those with large difference between mode field diameters.