The main source of fusion splicing loss between photonics crystal fibers (PCFs) and conventional fibers is from the mismatching of mode field diameters (MFDs) of fibers. We proposed a method to realize low loss splicing between small core diameter PCFs and conventional fibers. Using a fusion taper rig, we controlled hole collapse accurately to enlarge the MFDs of PCFs. As a result, the splicing loss of conventional fiber and PCF with quite mismatch MFDs can be decreased. Using this method a 0.2 dB splicing loss between a PCF with 3.94 μm MFD and a conventional fiber with 10.4 μm MFD was obtained experimentally.