The　pseudo-resonant-nuclide　subgroup　method　is　a　newly　emerged　self-shielding　calculation　method　to　treat　resonance　interference　effect.　It　has　been　implemented　in　the　NECP-X　code　which　is　developed　for　the　high-fidelity　neutronics　calculation.　Though　this　method　has　high　accuracy,　its　computation　time　occupies　more　than　half　of　the　total　computation　time　(mainly　including　resonance　self-shielding　calculation,　multi-group　transport　calculation　and　depletion　calculation).　To　improve　the　efficiency　of　the　resonance　self-shielding　calculation,　some　analysis　and　optimization　are　performed　in　several　aspects:　firstly,　the　maximum　number　of　subgroups　is　reduced　from　7　to,5;　secondly,　the　number　of　dilution　cross　section　points　is　reduced　from　21　to　9;　thirdly,　the　number　of　fuel　meshes　in　solving　SFSE　is　reduced　from　15　to　5;　finally,　number　of　fuel　meshes　in　solving　one　group　fixed-source　equation　for　the　SPH　factor　is　reduced　from　15　to　1.　The　acceleration　ratio　of　the　self　shielding　calculation　is　3.45　for　assembly　without　poison　and　3.49　for　assembly　with　poison.　The　time　proportion　of　self-shielding　calculation　is　reduced　to　less　than　30%.　The　accuracy　loss　is　negligible　in　the　accelerations.　Besides,　it　is　found　that　the　subgroup　condensation　scheme　can　obtain　better　self-shielded　cross　sections　of　component　resonant　nuclides　than　the　dilution　interpolation　scheme.