Abstract: The hyperfine burnup distribution of the fuel in Xi’an Pulsed Reactor (XAPR) of its steady state core arrangement in its first cycle was simulated by RMC. The thermal cross section of zirconium hydride in different temperatures was generated based on the operation temperature of XAPR. The k_eff of cold and hot experiments of XAPR with zero burnup was calculated. The highest three-dimensional burnup position of its first cycle was confirmed accounting for radial and axial discretization with temperature feedback effect. The result shows that the calculated axial burnup distribution of D5 and G14 fuel rods with 15 EFPD using radial sub-region method gets closer to the experiment result than that with no radial sub-region. The RMC is reliable in calculation of the hyperfine burnup distribution of the fuel in XAPR and can be used for reactor physics calculation and safety analysis for XAPR.