Fiber optic temperature sensors are accessibly affected by the light source drive current changes, the optical path bending, the splice loss and other intensity variables. In order to solve the temperature deviation caused by the light intensity variations, the system regularly updates the original incident spectrum to realize selfcalibration source waveform. The variation of ambient temperature causes the spectral drift of spectral analysis device which causes the deviation of temperature measurement. To solve this problem, the system uses wavelength locker to locate characteristic wavelength and uses spectral shift compensation method to achieve spectral selfcalibration. The optical multiplexing system is designed to achieve multi- channel fiber optic temperature measurement. Self- calibration verification experiments are designed to verify the validity of the system selfcalibration function. Experimental results show that the system self-calibrating temperature measurement deviation is less than ±1 ℃,when the environment changes. Therefore, the self-calibrating temperature measurement system can withstand the deviation of source spectral waveform changes, and make the spectrum analysis device overcome the interference of ambient temperature.