The diameters of UO2 fuel and B4C burnable poison particles in plate-type dispersed particle fuel are subject to manufacturing tolerances and therefore exhibit a statistical distribution rather than a single fixed value. This exacerbates the double heterogeneity effect and significantly impacts the accuracy of neutronics calculations. This study uses the Bamboo-Lattice code to quantify the effects of particle diameter distribution on the neutronics of plate-type dispersed particle fuel. Fuel particle diameters are assumed to follow a normal distribution with a mean diameter of 160 μm and a standard deviation of 10 μm, and a volume fraction of 0.2. Burnable poison particle diameters are also assumed to follow a normal distribution with a mean diameter of 80 μm and a standard deviation of 5 μm, and a volume fraction of 0.01. Using pseudo-random sampling and a confidence level of 0.99, cases with 3, 5, 7, 9, 11, and 15 discrete diameter values were generated to investigate the impact of the number of discrete diameter values on the calculation results. The validity of this discretization approach was confirmed through a sensitivity analysis comparing the results with a finer discretization. Results indicate that the diameter distribution of single-type particles has a negligible impact on neutronics calculations. However, for the UO2/B4C mixed particle configuration, the particle diameter distributions have a significant impact. Compared to a model using single diameter values (160 μm for fuel and 80 μm for burnable poison), the maximum difference in keff reaches 230 pcm at a fuel burnup of 65 MWd/kg. This study provides valuable guidance for assessing the impact of particle diameter distributions on core physics calculations and safety analyses of reactors utilizing plate-type dispersed particle fuel.