Abstract: Pebble-bed fluoride-salt-cooled high-temperature reactors (PB-FHR) have made progress to the stage of baseline designing of test reactor after more than ten-year pre-conceptual designing. Collision probability method was applied to solve the neutronic system of one pebble of PB-FHR, and attained its infinite multiplication factor and cell-homogenized few-group cross sections including total, capture and fission cross sections. The evaluation of accuracy of the output was based on comparison to a continuous-energy, doubly heterogeneous Monte Carlo reference model. Resonance calculation routine solved slowing-down equations on the ultra-fine lethargy mesh by collision probability method, through which the doubly heterogeneous system could be treated accurately. Results show that outputs from collision probability method are consistent with that of Monte Carlo reference model, and collision probability lattice code with ultra-fine resonance calculation is capable of generating few-group cross sections for PB-FHR.