Abstract: Wavelets expansion method can simulate the functions oscillating violently.It has been applied to simulate the violently variety of the angular flux,and has obtained satisfactory results.Neutron spectrum has violent oscillations within the resonant energy range.This paper introduces a method to discretize the energy variable of neutron transport equation by coupling the multi-group method and wavelets expansion method,which simulates the energy-dependent angular flux with wavelets scaling function within the resonant energy range and uses multi-group method within fast and thermal neutron energy ranges.The preliminary calculation results indicate that this method can obtain the accurate k-inf,as well as determine the fine-structure energy distribution of the angular flux,which is significant to resonance self-shielding calculation.