Abstract: The parameter sensitivity of reactor design in the reactor’s configuration was illustrated by using MCNP calculation with particle bed reactor (PBR) model for SNTP. The parameters include the outer diameter of the drum, the thickness of the reflector, the enrichment of ¹⁰B, the thickness of ¹⁰B, the pitch/diameter value of the fuel element, the height/diameter value of the core, and the pebble packing rate. The results show that the reflector thickness is decided by the outer diameter of the drum, and the variation of the enrichment and thickness of ¹⁰B have slightly controllable influence on core safety. There is an optimal value of pitch/diameter for PBR core. The neutron leakage rate can increase by increasing the value of height/diameter, which will further increase the control value of the drum. The k_eff increases, the neutron leakage decreases, and the energy spectrum becomes hardened when the pebble packing rate increases.In addition, the pebble packing rate increase has slight influence on the radial and axial neutron fluence rate inhomogeneous factor distributions. The results provide a reference for the future physical analysis of PBR.