This paper systematically studies the effect of scan line spacing on the sensitivity of laser-reduced graphene oxide based temperature sensor. As for the fabrication, we firstly sputter and pattern a pair of 80 nm thick gold electrodes on PET film, and then coat a layer of graphene oxide solution in the middle of the electrode. Second, graphene oxide is reduced by UV laser scanning to bridge the electrodes with the laser-reduced graphene oxide, which is a temperature sensitive material with temperature-dependent resistivity. A group of rGO temperature sensors are fabricated in this way with different scan line spacings ranging from 0.02 to 0.12 mm with a step of 0.02 mm. Raman spectroscopy analysis shows that the defects of graphene first decrease and then increase with increasing scanning spacing. The temperature calibaration results show that defects of graphene generally enhance the sensitivity of rGO temperature sensor, and the larger sensitivity is achieved with a scan line spacing of 0.02 mm and 0.12 mm.