The near-infrared femtosecond laser induced ferroelectric domain inversion in an important method in 3D nonlinear photonic crystal fabrication. Using structures produced by this technique， a series of attractive results have been achieved in optical frequency conversion and nonlinear wavefront shaping. At present， the reported laser induced domain inversion were all implemented at room temperature. For ferroelectric crystals， it would reach the Curie point during heating， and many characterizations such as coercive field which relate to domain inversion may change seriously. However， the effect of crystal temperature on femtosecond laser induced domain inversion is undefined. In this work， the strontium barium niobate （Sr_xBa_1-xNbO₃） ferroelectric crystal with the Curie point of about 70-80 ℃ depends on component proportion of Sr and Ba was used for domain inversion. Direct near-infrared femtosecond laser writing was implemented at the temperature of 25-65 ℃. The domain inversion condition was judged based on the second-harmonic pattern in the far field. The variation tendency of threshold laser power for domain inversion depends on temperature was tested and possible reason was predicted.