A high Er3+-doped narrow linewidth fiber laser based on fiber Bragg grating (FBG) Fabry-Perot (F-P) cavity was demonstrated. Spatial hole burning effect was restrained by fiber Faraday rotator. Two short FBG F-P cavities were used as narrow bandwidth filters to discriminate and select laser longitudinal modes efficiently. Stable single frequency 1534.83 nm laser was acquired. Pumped by two 976 nm laser diodes (LDs) and two ends output, the fiber laser exhibited 12 mW threshold. Total 39.5 mW output power and one end 22 mW output power were obtained upon the maximum 145 mW pump power. Optical-optical efficiency was 27% and slope efficiency was 29.7%. The output power tended to be saturated when pump power increased. The 3 dB linewidth of laser was less than 7 kHz, measured by the delayed self-heterodyne method with 15 km single mode fiber. The high power narrow linewidth fiber laser can be used in high resolution fiber sensor system.