In order to improve the service efficiency of the wavelength resources in the optical network, a tunable four-channel wavelength converter based on Ge-doped photonic crystal fiber was proposed by using the theory of transient stimulated Raman scattering in optical fiber. Since the gain of the stimulated Raman scattering effect will change with the frequency shift between the signal light and the probe light wavelength, the wavelength of each conversion channel can be tuned by controlling the wavelength of the probe light. The influence of pump input power on the performance of multi-wavelength converter was analyzed, and the results show that the conversion performance of the multi-channel converter is better with the increase of the input pump power. The simulation was calculated by OptiSystem with four-channel tunable probe signals. Simulation results show that the four-channel tunable wavelength converter can simultaneously achieve four-channel wavelength conversion, each channel wavelength can be tuned from 1511nm to 1569nm.