Semiconductor fiber temperature sensors have been used widely in many fields, but most of them pick up temperature by measuring the optical intensity of certain fixed narrow-band in absorption spectrum. Furthermore, they are sensitive to the loss of optical intensity and the fluctuation of light source power. The novel temperature measurement system proposed in this paper is based on the semiconductor absorption theory and the spectral analysis of method. To measure temperature, the sensor model detects not the certain narrow-band spectrum but the most spectra of the optical absorption edge. Therefore the measurement accuracy and the stability can be improved greatly. Experimental results are in agreement with theoretical analysis results perfectly.