Abstract: In the experiment,we adjust LD's wavelength by control of temperature and analyze the characteristics of fiber laser. The fiber laser in this experiment is composed of a high-power LD pumped with output wavelength of 970nm and a double-clad fiber spliced fiber Bragg gratings (FBGs) at both ends. Experimentally through a taper fiber,we have realized 5.1W of output power at 1100nm,with the highest conversion efficiency of 63%.