Abstract The discrete ordinates particle transport codes (SN codes) are widely used in reactor design, radiation shielding, nuclear detection and other fields. SN automatic modeling system (SNAM) is an integrated interface program between CAD systems and SN codes, which makes full use of CAD technology to improve SN modeling and perform the conversion between CAD models and SN code input files. The modeling capability of SNAM has been tested by the International Thermonuclear Experimental Reactor (ITER) benchmark model in this paper. The benchmark process includes geometric model processing, material assignment, model normalizing, converting to SN code input file, calculating and analysis with SN code system VisualBUS. The neutron flux radial distribution of the inboard blanket modules is given and compared with the results calculated by MCNP.