The seismic performance of press fittings is studied, which is one of the weldless joints of stainless steel pipe used in the water piping of recent fire protection system. The piping of this study was constructed based on the piping connection reference of NFPA 13. The permissible displacement of the piping was set as the allowed amount which is given in the Building Structure Standard, and the measurements were repeated 10 times. The Von-mises stress of the piping was 2.48 and 1.25 times of the allowed amount of stress, which was less than the standard, noted three times on the NPPs Allowable Stress for Level D service loading. Therefore, the press fittings shows enough seismic performance.