Based on the analysis of the basic characteristics of fiber Bragg grating external cavity semiconductor laser(FBG-ECL),the frequency tuning methods for this type of lasers are investigated,including temperature tuning method and stress tuning method.The center wavelength of fiber Bragg grating is changed by the axial stress tuning method to realize the frequency tuning.The piezoelectric ceramic(PZT) was used to exert an axial stress on the grating,and the amount of change in the center wavelength of the fiber Bragg grating was controlled by adjusting PZT drive voltage.The experimental results show that,for the FBG-ECL with wavelength 1550 nm,when the PZT drive voltage adds up to 126 V,tuning range can reach 100 GHz and tuning speed can reach 2 ms per cycle.