In this study we analysed the longitudinal variations of phase scintillation during geomagnetic storm by using VTEC,ROT &ROTI on March 16-18, June 22-23 and December 19-21/ 2015.We used GPS data of TEC for selected days with IGS stations codes and geomagnetic coordinates from North America in Canada: CAGS(45.6°N, 75.8°W) & ESCU(47.1°N,64.79°W) and world Europe in Italy:BGRZ-(46.49°N,11.3°E),Ukraine: MIKL(47.0°N,32.0°E),Switzerland:ZIMM(46.9°N,7.5°E),Slovakia:GANP(49.0°E,20.3°E)and Austria: GANP(47.1°N,15.5°E). The geomagnetic storm data was taken from Kyoto University. The Material was used to studied this study using UNAVCO down load software, GGrun 2016 ,and matlab The TEC data are downloaded from UNAVCO data home page http://facility.unavco.org/data/gnss/perm-sta.php.We have observed ionospheric phase scintillation in Canada, but all the rest six countries have not observed ionospheric phase scintillation in March 16(initial phase). We have also observed ionospheric phase scintillation in Canada and Italy, we have not observed ionospheric phase scintillation in Austral, Slovakia, Ukraine and Switzerland in March 17(main phase).We have observed ionospheric phase scintillation in Italy, Canada and Austria and Slavonia and Ukraine and we have not observe ionospheric phase scintillation in Swaziland in March 18(recovery phase).We have observed ionospheric phase scintillation in Italy, Austria, Canada, Slavonia, Ukraine and Swaziland in June 22(initial phase).We have observed ionospheric phase scintillation at Canada and we have not observed ionospheric phase scintillation in and we have not observed ionospheric phase scintillation in Italy, Austria, Slavonia, Ukraine and Swaziland in June 23(main phase).We have observed ionospheric phase scintillation in Italy, Canada and Swaziland and we have not observed ionospheric phase scintillation in, Austria and Slavonia were observed strong fluctuation, Ukraine in June 24(recovery phase). We have observed ionospheric phase scintillation in Slovakia and the remaining countries did not have observed ionospheric phase scintillation in December 19(initial phase) .We have observed ionospheric phase scintillation Canada and the remaining countries were not observed ionospheric phase scintillation in December 20 (main phase) .We have not observed ionospheric phase scintillation in December 21(recovery phase) observed in all station. Generally ionospheric phase scintillation dependant on longitude.