Bio-source materials have attracted wide attention due to their rich sources, recyclability, pollution-free and multi-functional properties. Herein, a lithium-sulfur battery interlayer was obtained by slicing the birch at different angles, following with the delignification and carbonization processes. Biochar containing lots of micropores and mesopores shows a specific surface area up to 267.7 m ²/g. The biochar interlayer sawing along 45° achieved the highest electrochemical performances. Based on this biochar interlayer, lithium-sulfur battery exhibits a high initial capacity of 979.4 mAh/g at 0.2C (1C=1650 mA/g) and retains a discharge specific capacity of 625.4 mAh/g after 200 cycles, which degrades only 0.18% per cycle. Furthermore, the hierarchical microchannel and transpiration of birch effectively adsorb polysulfide and reduce the shuttle effect, suggesting that it can be widely employed in commercial lithium sulfur battery.