Abstract: To perform realistic core calculations, few-group neutron cross-sections library by functions of burn-up and thermal hydraulics parameters should be prepared in advance. Traditional deterministic parameterization process is based on the macro cross-section. However, this method should consider the historical effect of some physical states, which increases the number of calculation branches. Thus, this paper proposes a new parameterization process based on the micro cross-section of nuclide. This method effectively eliminates the historical impact. Therefore, only burn-up and material temperature need to be considered. The calculation process is performed by RMC code. Firstly, all of material nuclides micro cross-section and nuclides density is calculated. Then, macro cross-section is obtained by the micro cross-section lib. To test the method accuracy, a self-design pressurized water reactor model is built. The test results agree well with the reference results calculated by RMC full core calculation.