Erbium-doped superfluorescent fiber sources (SFS) pumped near 980 nm in double-pass backward (DPB) configuration have been characterized through theoretical simulation. The results indicate that for a DPB SFS with a reflector of any reflectance, the pump-power independent mean-wavelength operation can always be achieved by properly adjusting the erbium-doped fiber (EDF) length. In the case of high stable mean-wavelength operation, the DPB SFS with the optimized reflector has a linewidth and pump efficiency obviously larger than SFSs in other configurations.