The high temperature characteristics of long period fiber grating (LPFG) and its strain characteristics at high-temperature with asymmetric refractive index profile in cross section of fiber induced by high-frequency CO2 laser pulses on common communication fiber (corning SMF-28) were proposed. Experimental results show that the LPFG resonant wavelength shifts linearly when the temperature changes from 200 ℃ to 1000 ℃, and the resonant wavelength shifts linearly with the increase of strain at high-temperature as well. In addition, the measurement sensitivities of strain and temperature were different because the fundamental guided mode was coupled to the different cladding modes.