Abstract: Lead-based fast reactors have good natural circulation capabilities, and its natural circulation characteristics is of great value to improve the inherent safety of the reactor, and the scaling analysis method is the theoretical basis for establishing a reasonable and feasible lead-based fast reactor natural circulation test facility. In this paper, the main similarity groups could be determined by using dimensionless fluid governing equations of typical natural circulation lead-based fast reactor primary cooling system. Based on the constructed dimensionless similarity groups, the scaling analysis of small natural circulation lead-based fast reactor named SNCLFR-10 was carried out to obtain the geometric and thermal hydraulic design parameters of the dual-loop single-phase natural circulation experimental facility. The scaling method of the lead-based fast reactor natural circulation test facility was verified by comparing and analyzing the key thermal and hydraulic parameters of SNCLFR-10 and the scaled-down test facility under rated conditions. The research results show that the key thermal-hydraulic parameter ratios of SNCLFR-10 and the scaled-down facility are in good agreement with the theoretically deduced ratio, and the established lead-based fast reactor natural circulation experimental facility scaling analysis method is reasonable and feasible.