A singlemode-multimode-singlemode (SMS) fiber structure for temperature measurement using an optical time domain reflectometer (OTDR)-based interrogation system is proposed. A temperature measurement range of 40 ℃-195 ℃ with a resolution of 0.12 ℃ and a linearity of 0.992 could be achieved for the multimode fiber (MMF) graded index with a length of 60 mm. It was also demonstrated that two-point temperature measurement with two SMS fiber structures as temperature sensors could be made. The proposed temperature measurement system offered a high resolution and also benefited from a simple configuration with a capability of multi-point temperature measurement.