Abstract: Polypyrrole/carbon fiber (PPY/CF) paper electrothermal composites were prepared by polymerizing pyrrole monomers on carbon paper (CPP) by gas phase polymerization. The PPY/CF paper composites were tested by FTIR, SEM and XRD, the optimum mass fraction of CF in CPP and the optimal solubility of FeCl₃ were investigated. The mechanical properties and electrothermal properties of PPY/CF paper composites were studied. The results show that PPY/CF paper composites are successfully prepared, and PPY is mainly attached to aramid pulp; The PPY/CF paper composite prepared with CPP precursor with 10 wt% CF mass fraction and FeCl₃ with concentration of 1.2 mol/L has the lowest resistivity, which is 0.139 Ω·cm. The PPY/CF paper composite has a significant increase in mechanical properties compared with CPP. And under the low voltage, the PPY/CF paper composite has the advantages of stable electrical conductivity, remarkable heat generation effect and good thermal stability.