Semi-interpenetrating polymer network of coal/polyaniline (PANI) composite material were prepared by in situ polymerization. Raw coal was oxidized in different conditions by H2O2 and HNO3, respectively. The total acidic groups analysis, Fourier transform infrared (FTIR) spectrum, and conductivity test of the raw coal and the oxidized coal/PANI composite material were conducted. The results showed that the increases of the carboxyl groups and the hydroxyl groups were mainly attributed to the hydrolysis of the weak ether link and the transform from the carboxylate to carboxylic acid. These increases were benefit to the reaction of coal and PANI, and consequently enhanced the conductivity of the composite material. The maximum conductivity of oxidized coal/PANI reached 4.72×10‑1 S/cm.