In this paper, a fiber-optic temperature sensing system, based on surface plasmon resonance (SPR) and integrated with a smart-phone platform, is proposed and demonstrated. The sensing system is composed of a side-polished-fiber-based SPR sensor, which is illuminated by the LED flash from one end, and the output signals are recorded and processed by the camera and a designed application in the smart-phone. The sensing performance is evaluated by immersing the sensor in distilled water under different temperatures. Experimental results show that the measurement resolution of the proposed temperature sensor can reach 0.83°C in the range from 30 to 70°C, corresponding to a linear correlation coefficient of 0.9798. The low-cost and portable fiber optic SPR sensor based on a smart-phone platform has wide application potentials in the fields of health-care, environmental monitoring, etc.