To manage the forming process of poly(tetrafluoroethylene) (PTFE) properly, we attempted to pursue the crystallographic properties via X-ray diffraction (XRD) measurements and elucidated that the deformation capability of the PTFE materials can be evaluated via XRD measurements. Because of its unique and utility properties, PTFE has been one of the most significant polymers in various industries. Although PTFE is categorized into thermoplastic polymers, usual forming methods of thermoplastic polymers are not available for PTFE. To fabricate stuffs, PTFE particles are formed into desired shapes and then sintered. At the forming process, deformation capability (malleability) of the PTFE particles is a key to obtain dense and rigid bodies. The deformation capability has been ascribed to crystallographic properties of the PTFE particles. Since the room for further deformation of PTFE decreases when deformed by external forces, versatile methods to assess remaining deformation capability of PTFE have been required. With the reliable and convenient characterization method at hand, it will be possible to optimize the PTFE forming processes situationally.