Hole inflation and tapering techniques have been rated effective methods to change the structure parameters of the photonic crystal fibers (PCFs). Hole inflation can change the air-filling faction, that is, the hole diameter and pitch of the PCFs and tapering can change the core diameter while preserving the cross section of the original PCFs. Controllable-change of the structure parameters of the PCFs allows some special PCF devices to be made,and is of great significance to further realize the potential applications of PCFs.