Because of deficient bandwidth, the space resolution of Distributed Optical Fiber Raman Temperature Sensor (DOFRTS) is low. When the sensing length of fiber is close to space resolution, there is no accurate temperature response. For solving the problems, a new linear algorithm is proposed. Firstly, the relationship between Raman ratio and temperature and the characteristics of frequency response are analyzed, and then a mathematical model is built up for this algorithm. A single-mode temperature sensor system for 10 km long is built up, some related experiments are carried out by using the algorithm. Experiment results are consistent with theoretical analysis, the temperature amplitudes of testing fiber from 3 meters to 6 meters are corrected. The temperature measurement accuracy reaches 1℃ and measuring time is 40 seconds. By applying this algorithm, the limit of bandwidth can be overcome effectively and the system cost is cut down obviously, at the same time, space resolution, temperature resolution and measuring time are optimized.