A sub-nanometer linewidth, near-diffraction-limited superfluorescent source with a record power of 1509 W based on all- fiber master oscillator power amplifier (MOPA) configuration is established. The slope efficiency of the main amplifier is up to 85.2 % and the beam quality at maximum power stays stable around M 2= 1.4. The back reflection power maintains a linear behavior which confirms the considerable stimulated Brillouin scattering (SBS) suppression capability of our system. The performance of this high power source is robust with respect to the environment perturbations. No self-pulsing and relaxation oscillation is observed in the whole power range.