In electrocatalytic CO₂ reduction reaction (CO₂RR), metal-free Se-based multi-doping carbon has become a new focus. In this paper, a series of metal-free Se, B, P, N doped carbon-based catalysts (Se-BP-N-C) were prepared by a simple and scalable pyrolysis method. The electrocatalytic CO₂ reduction results show that, the main product on Se-BP-N-C catalyst is CO, and there are no other by-products except H₂. Specifically, the optimal one prepared at 1050 °C (named Se-BP-N-C (1050)), can selectively reduce CO₂ into CO with Faradaic efficiency (FE) up to 96.2% (at − 0.5 V), and maintains long-term stability after continuous electrolysis for 10 h in a flow cell (current density remained 82.7%). This study would provide a good reference for designing advanced efficient metal-free catalysts in electrocatalysis.