By using camphorsulfonic acid (CSA) to protonate polyaniline (PANI), the counterion enabled the PANI-CSA complex processable as a solution phase. So camphorsulfonic acid (CSA)-doped polyaniline/polyimide (PANI/PI) blend films were prepared by the solvent casting method using N-methylpyrrolidinone (NMP) as a cosolvent followed by thermal imidization. The conductivity of the PANI-CSA/PAA (50 wt % PANI content) is greater than that of the pure PANI sample at room temperature. As the thermal imidization proceeded, molecular order of polymer chain structure was improved in the resulting PANI-CSA/PI film due to the annealing effect of PANI chain, and this PANI-CSA/PI film showed higher conductivity than PANI-CSA and PANI-CSA/PAA film. PANT-CSA/PI blend films had a good thermal stability of conductivity at high temperature.