The invention provides a high temperature resistant doped fiber temperature sensor, which comprises an optical source, an optical splitter, a reference optical path, a sensitive optical path, an optical power meter, and a data processing and storing device. The reference optical path and the sensitive optical path are connected in parallel, one end thereof is connected with the optical splitter and the optical source in sequence, and the other end thereof is connected with the optical power meter and the data processing and storing device in sequence. The reference optical path and the sensitive optical path are both sensitive fibers. The high temperature resistant doped fiber temperature sensor adopts a doped sapphire crystal material as a sensitive fiber. The material comprises a fiber core and a cladding material coated outside the fiber core. The preparation process of the fiber core is simple, and has excellent absorption characteristics and up-conversion intensity, thereby greatly improving the application range of the sapphire fiber. The cladding material uses multi-component phosphate glass doped with polycrystalline alumina and Er3+, is low in cost, and can meet requirements of total reflection. The sensor is high in detection sensitivity and accurate in result.