Lithium-sulfur (Li-S) batteries are an attractive candidate for the next generation energy storage systems. However, the practical use of Li-S batteries is hindered by poor cycle life and low Coulombic efficiency, which are induced by shuttle effect. Modifying the properties of a separator is an effective way to inhibit the shuttle effect. However, only physical interactions of common carbon materials are not enough to confine lithium polysulfides. In this paper, a porous carbon nanowire (N-PCNW) is designed to modify the separator. The N-PCNW with high N-doped level (7.12 wt%) not only possesses excellent electron conductivity, but also traps the soluble polysulfides effectively with both physical and chemical interactions. With the N-PCNW modified separator, the pure sulfur cathode exhibits enhanced electrochemical performance, showing a high initial discharge capacity of 1430 mA h g(-1) at 0.2 C (1 C = 1675 mA h g(-1)) and good long-term cycling stability at 0.5 C with 0.08% capacity fading per cycle. This design is easy and efficient, providing a great promise for the pratical use of Li-S batteries. (C) 2016 Elsevier B.V. All rights reserved.