The invention discloses a method for implementing power equalization of a DWDM system, comprises: Measure and calculate, respectively, a gain spectrum characteristic curve of an optical power booster amplifier unit and a loss spectrum characteristic curve of a loss device with related wavelengths in the DWDM system; Subtracting the loss spectrum characteristic curve from the gain spectrum characteristic curve to obtain a difference curve, taking the complement curve of the difference curve as a loss characteristic target curve of a GFF; Setting in the optical power booster amplifier unit a GFF having loss characteristic curve coinciding with the loss characteristic target curve. The invention synthetically considers gain spectrum of an optical power booster amplifier unit and loss spectrum of a loss device with relating wavelengths to define a loss characteristic curve which a GFF should have. In this way, optical power flatness of every channel is effectively guaranteed. Therefore, transmission link flatness of whole system is guaranteed, and channel optical power equalization property of a system is further improved.