Abstract: Multi-column interlinking is an effective separation method adopted for enrichment of trace deuterium and tritium. Conceptual design and proper operating mode were proposed for separation of H₂/HD by cryogenic distillation with three interlinking columns, and separation performance was obtained. Enrichment of 20×10×10 achieved with proper operating mode indicates that multi-column interlinking is specially suitable for trace composition enrichment. The effects of pressure and reflux ratio on separation performance were also investigated. As pressure increases from 0.06 MPa to 0.15 MPa, deuterium stripping efficiency drops from 99.79% to 99.44%, and as reflux ratio increases from 3 to 5, deuterium stripping efficiency increases from 99.67% to 99.81%.