Biomass materials like bamboo have received much attention in studies of triboelectric nanogenerators (TENGs) electrode materials because its sustainability, however, it is a major challenge to construct high-quality conductive networks, originating from the agglomeration of conductive fillers and inferior interfacial properties. In this work, the continuous steam explosion in-situ coating technique (CSEICT) was innovatively adopted to fabricate bamboo/graphene/PVA composites (BGP) with an advanced structure of graphene in-situ coated on the surface of bamboo fibers. The BGP-based triboelectric nanogenerator (BGP-TENG) possessed a high output charge density of 155.86 μC/m2, 1.57 times higher compared with that of natural wood. The BGP-TENG was proven to be used as smart floors to harvest human walking energy. Notably, the BGP had extremely high electromagnetic interference (EMI) shielding effectiveness of 51.51 dB, electrical conductivity of 101.86 S/m with ultra-low percolation threshold of 0.06 vol%, and outstanding and stable electro-thermal management capabilities. On this basis, this work can provide a novel strategy for preparing bio-based composites and further expand the multiple functions of bio-based TENGs.