Abstract: Based on real-time response of DS18B20 to external temperature, digital temperature sensor DS18B20 is placed in the same temperature field as the temperature fiber Bragg grating (FBG) connected with the spectrometer. Taking field-programable-gate-array(FPGA) as a data processing and control chip, real-time monitoring and display system on the temperature field change is designed through serial port to send intelligent instructions. This method does not need thermostat to control temperature, which reduces the cost and power consumption of FBG wavelength calibration. Experimental results show that the linearity of wavelength-temperature curve is 0.999, and the temperature sensitivity coefficient of FBG is 9.899 pm/℃, which differs from the result 10.468 pm/℃ measured with thermostat to 0.569 pm/℃. The error falls in the range of 0.619 pm/℃ allowed by the system, which verifies the accuracy of the method.