Abstract: In order to achieve low boron operation of pressurized water reactors (PWRs), neutronics design and analysis of dispersed particle burnable poisons were carried out, the self-shielding effect of dispersed particle burnable poison could be adjusted by the particle radius, which could achieve a better match between burnable poison consumption and fuel burnup. The commonly used fast burn-up burnable poisons B and Gd were selected in this paper, and the influence of different particle radii and packing fraction of the dispersed particle burnable poisons on the neutronics characteristics was studied. The results show that dispersed particle burnable poisons can achieve long-term stable reactivity control, BISO boron-containing particles can meet the requirements of the low boron operation of long cycle PWRs and are suitable as candidate burnable poisons for long cycle PWRs for further research.