Abstract: In order to investigate the analysis methodology for k_eff sensitivity to nuclear data in continuous-energy Monte Carlo codes, the theory about calculating the eigenvalue sensitivity coefficients to nuclear data is introduced. And the foundation of the Iterated Fission Probability（IFP） method which is widely used for calculating the adjoint flux in continuous-energy Monte Carlo codes and approaches for tallying the adjoint-weighted reaction rates are discussed. Finally, with the continuous-energy Reactor Monte Carlo code RMC, sensitivity analysis is performed on a polyethylene sphere criticality benchmark based on the IFP method and the results are compared to those calculated by SCALE.