A sapphire fiber fluorescence thermal probe with Cr3+ ion-doped end is grown from the laser heated pedestal growth（LHPG）method.The fluorescence thermal probe has the advantages of compact in structure

high performance and ability to detect temperature ranging from the room temperature to 450 ℃.Through lock-in amplifier

the noise out of the signal can be effectively decreased

so that the signal-to-noide ratio can be improved.Based on the theoretical analysis of the fluorescence temperature measurement methodology and fiber technology

a phase-sensitivity measurement based on Hillbert transformation is adopted to make the real-time measurement.