Abstract: The principle of distributed optical-fiber temperature sensor, based on Raman scatter and Brillouin scatter, is discussed by this paper, which adopts the frequency analytical method. The analytical method can overcome the shortcoming of the traditional temporal analytical method, which needs high-speed sample circuit. Furthermore the analytical method has broke a new path to enhance the spatial resolution of sensors. At the same time, a high spatial resolution optical-fiber sensor based on model coupling is discussed by this paper. Finally the comparison of several optical-fiber sensors are presented.