By using Er3+-doped fiber, a single-mode fiber laser based on fiber Bragg grating was developed. When it was pumped by 980 nm laser-diode, the output spectral bandwidth was measured as 0.1 nm at 1.56 μm. The max. output power was measured as 1.73 mW. The power stability is better than ±0.02 dB, and the stability of output wavelength is better than 0.05 dB. The laser had a threshold of 7 mW and a slope efficiency of 3%.