An all-fiber temperature sensor based on reduced graphene oxide (rGO) is studied. Such a sensor consists of two key parts, including a section of side polished fiber (SPF) as a substrate and rGO film as temperature sensitive material which is deposited onto the SPF by spontaneous evaporation. Experimental results show that temperature change can affect the interaction between rGO film and propagation mode in SPF, and change the transmitting optical power through rGO-based SPF sensor. When temperature changes from -7.8 ℃~77 ℃, the transmitting optical power of the sensors spans over 11.3 dB. The sensitivity and temperature measurement accuracy of the rGO-based SPF sensor are measured to be 0.134 dB/℃ and 0.03 ℃, respectively. The linear correlation of the sensor between temperature and transmission optical power is 99.4% and response rate is at least 0.0228 ℃/s.