In summary, RTP fibers (B-fibers) were produced from natural bamboo by partial delignification. Attributed to the interactions between cellulose, hemicelluloses and lignin, the as-obtained B-fibers exhibited long-lived RTP emission (lifetime of 294.9 ms). Moreover, Bfibers with red afterglow emission were obtained by simply treatment with RhB via an energy transfer process. The B-fibers and B-fibers/RhB were easily processed into multifunctional RTP materials. Different from the traditional "bottom-up" methods used to produce RTP materials, which are costly and have negative environmentally impacts, the as-developed "topdown" RTP B-fibers can be easily produced from bamboo. Our results provide a practical route for producing sustainable RTP fibers at low cost and on a large scale.