In this study, a numerical analysis and an analysis of variance (ANOVA) are applied to find the best suitable neutronic parameters for the performance analysis in a thorium fusion rector. The numerical and ANOVA approach are employed to investigate the neutronic characteristics of a fusion reactor using ThO2 90% + FR spent fuel 10% fuel mixtures. Three different neutronic parameters for the ANOVA and numerical approach, namely, moderator/fuel volume fractions (V-m/V-f), plasma chamber dimensions (PCD) and neutron wall loading (NWLs) as time dependent are selected for neutronic performance characteristics including tritium breeding ratio (TBR), multiplication factor (M), total fission rate (I (f)) pound, Th-232(n,gamma) reaction, burn up and/or transmutation (B/T) and fissile fuel breeding (FFBR). Moreover, effects of the NWLs, V-m/V-f fractions and PCD in the B/T of FR spent fuel mixed thorium are investigated. Numerical and statistics approach results are evaluated for TBR, M, I (f) pound fission rate, Th-232(n,gamma) reaction, B/T and FFBR.