The performance of fiber Bragg grating (FBG) wavelength demodulation system based on tunable laser is affected by many factors,such as the control circuit and modulation pa rameter of laser, performance of photodetector,acquisition and amplification circuit of weak sign al.Scanning frequency is one of the most important parameters in laser modulation,and its effects on the FBG wavelength demodulation system are studied.This paper finds that the error of wavelength de modulation varies with the scanning frequency.In this paper,the error of wavelength demodulation and the scanning frequency of the laser are fitted,and the fitting results are embedded into the demodulat ion program to compensate the real-time error of the demodulation wavelength under the current laser scan ning frequency.The effect of error compensation is verified by experiments.The results show that t he maximum error of wavelength demodulation is improved by 6.0times and the error of wavelength dem odulation and standard deviation (SD) caused by laser scanning frequency are respectively reduced by 2.2times and 1.9times.Finally,the demodulation error of FBG wavelength demodulation system based on tunable laser is limited to 1.38pm,which it can effectively meet the accuracy and stability of demodulation wavelength in high-speed FBG wavelength demodulation system,and can be used in the demodulation of high-fre quency dynamic signal.