A novel Yb3+-doped double-clad fibre laser based on a double-clad fibre Bragg grating is presented. The fibre Bragg grating, as the output mirror, has been formed in Yb3+-doped double-clad fibre with the phase-mask method. When the input pump power is 2.8 W, the maximum laser output power is 570mW, with ＜ 0.2 nm in line-width at the wavelength of 1.058μm, over 40dB signal-to-noise ratio and 24% slope efficiency.