Lithium–sulfur batteries (LSBs) are promising candidates for next-generation high-performance batteries due to their high energy density, low cost, and environmental friendliness. However, issues such as low active material utilization, volume expansion, and serious shuttle effect have severely restricted their practical application. Herein, two 3D covalent organic frameworks (COFs), TFPB-TAA and TFPB-TAB with pto topology, are synthesized and applied as cathodes materials in LSBs. The abundant porosity in the 3D pto structure helps inhibit the shuttle effect and enables uniform sulfur distribution. Density functional theory calculations predict their strong polysulfide adsorption capacity. Impressive initial capacities of 1288 mA h/g for TFPB-TAA and 1192 mA h/g for TFPB-TAB are achieved at 0.1C along with exceptional capacity retentions of 69.3 and 73.5% at 0.5C after 400 cycles. This work provides new insights into the design of 3D COFs for advanced LSBs.