Sluggish polysulfide conversion (SPC) process combined with shuttling effect and poor electronic conductivity of sulfur become the main obstacles in hindering the commercial application of Li-S battery. In this study, to address these issues, CAU-17 derived bismuth nanoparticels embedded in nitrogen doped carbon belts is proposed as a catalyst layer on separator for high performance Li-S batteries. By incorporating the excellent electronic conductivity of bismuth metal nanoparticles, the abundant polar adsorption sites of nitrogen-doped carbon belts, and tailored adsorption space on such “metal-carbon hybrid architecture”, the promotion of the polysulfide nucleation as well as effective conversion efficiency in SPC process have been achieved. Density functional theory computation further confirms the enhanced adsorption energy of bismuth nanoparticles to dissolved polysulfides during SPC process. Benefitting from the unique architecture and rational catalytic design, the Li-S battery with bismuth nanoparticles embedded in nitrogen doped carbon belts modified separator possesses a high specific capacity of 1045 mAh g−1 at 0.2 C and maintains a satisfactory specific capacity of 612.8 mAh g−1 at 4.0 C. Simultaneously, the decent high-rate cycling stability is achieved after 500 cycles. This work deepens the understanding of designing a metallic-based electrocatalyst layer on separator for high performance Li-S battery.