Abstract: Polypyrrole (PPy) was in-situ polymerized on the surface of biological template-cellulose nanofibers (CNFs) to form the CNF-PPy complexes, which further were uniformly dispersed into natural rubber (NR) elastomeric matrix to prepare CNF-PPy/NR conductive elastomers with high flexibility. The results show that CNFs can assist PPy to form a three-dimensional network structure in NR matrix, improve the mechanical properties and electrical conductivity of elastomers, and reduce the percolation threshold effectively. When adding 5% CNF(rubber mass as 100) and 20%PPy, the tensile strength of CNF-PPy/NR is (8.97±0.92) MPa, which is about 1.56 times of PPy/NR and 9.54 times of pure NR, respectively, and the conductivity is up to (0.134±0.063) S/m; At 0.3 A/g current density, the specific capacitance can reach 96 F/g, and it can still maintain its initial value of 72% in the cycle of charge and discharge 1 200 times with 1.0 A/g current density. The conductive elastomer exhibits good mechanical and electrical properties, which is expected to be applied in the field of flexible organic electronic devices.