The graphene oxide/polyaniline composites were synthesized by in-situ chemical oxidation polymerization using Cl-, CSA- (camphor sulfonic anion group) and SO42- as counter anions, with 1 mol/L proton concentration and ammonium persulfate as initiator. SEM, FTIR and XRD analyses were conducted to characterize the morphologies and structures, four-probe method and vector network analyzer were employed to determine the electromagnetic parameters. The impedance and reflection loss (RL) were calculated. The results indicated that the three types of composites appear to be sandwich-like structure with graphene oxide layer coated by polyaniline nanocones. The electronic conductivity reaches 5.500 S/cm portending higher dielectric loss capacity, when the para-anion is SO42-. While the standing-wave ratio of CSA doping composite is up to 1.1 at 14.2 GHz and much closer to a traveling wave state suggesting the best impedance matching, whose minimum RL reaches -30 dB (9.925 GHz, 2.75 mm) and effective absorbing bandwidth (RL<-10 dB) reaches 4.845 GHz (12.305~17.15 GHz, 2 mm).