In order to improve the high temperature sensing properties of the lon g period fiber gratings (LPFGs),an improved point-by-point inscription method is proposed to fabricate LPFGs.The method pr inciple is scanning a rectangular part on the fiber core to reduce the sensitivity to misalignment between the core and the focus.An LPFG is inscribed successfully in no-hydrogen-loaded SMF-28fiber using this method by controlling femtosecond laser,with the align ment of the fiber core systems containing dual-CCDs and high-precision electric displacement platform.And the attenuation depth o f －19dB within the wavelength range of 1250－1400nm is obtained in the LPFG whose length is 16mm.Then,high temperat ure character istics experiment is performed on the LPFG by a high temperature tube furnace.An sensitivity of 139.27pm/℃ and a linearity of 0.993within the temperature range of 300－800℃ are achieved.It is demonstrated that the LPFGs fabricated by the improved point-by -point inscription method are very suitable for the high temperature measurement.