In order to obtain the optimum transmitting power required to reach the maximum transmission distance under nonlinear constraints, makes it possible for software to customize optical access network. For the commercial wavelength division multiplexing passive optical network (WDM-PON）with STM-16 and STM-64 of external modulators are modeled and analyzed under different wavenumbers (4λ, 以 λ and 16λ）, The power of optimum transmitting and maximum transmission distance are analyzed, respectively. Network model were composed of standard single-mode fiber SSMF-2以, 1 :64 passive fiber branching at its far end (RN）, optical line te rminal (OLT）and optical network unit (ONU）. In order to improve the network utilization and receiving efficiency, the influence of different wavenumbers and transmission distances on the performance of high data rate WDM-PON system is analyzed. In order to save power consumption, the configuration of each multi-band PON is optimized in terms of transmission power.