Recently, commercial wearable electronic devices have gradually attracted research interest in flexible batteries. The electrode is the crucial component of a flexible lithium-sulfur battery, which restricts the development of flexible lithium-sulfur batteries (LSBs). Here, NiCoSe/holey carbon nanosheet in situ grown on carbon cloth (NiCoSe/CNS/CC) was successfully synthesized and used as an efficient sulfur host for the flexible sulfur cathode. Its special structure also provides optimal conditions for the loading of sulfur and promotes efficient transport of both electrons and Li-ions. Numerous polar NiCoSe nanoparticles are attached to the surface of carbon fibers, which can effectively anchor lithium polysulfides (LiPSs) by chemisorption and accelerate their conversion. Benefiting from this special architecture and the polar NiCoSe nanoparticles, the NiCoSe/CNS/CC/S demonstrates excellent electrochemical performance. At 1C, the NiCoSe/CNS/CC/S electrode delivers a discharge capacity of 454 mA h g−1 after 600 cycles. Furthermore, even at 2C, after 600 cycles, it still maintains a capacity of 426 mA h g−1, with a capacity decay of 0.079% per cycle. The NiCoSe/CNS/CC/S electrode enriches the flexible sulfur cathodes with its excellent electrochemical and mechanical properties while providing a new path for the research of flexible LSBs.