With various mole ratio of aniline to ammonium persulfate and by low temperature chemical oxidation polymerization, fibrous polyaniline (PANI) was successfully prepared, using camphorsulfonic acid as doped acid. The effects of mole ratio of monomer aniline to initiator ammonium persulfate on the morphologies and structures of polyaniline were characterized by TEM, SEM, FT-IR,etc. The electrochemical performances of all the samples were investigated by cyclic voltammetry (CV), galvanostatic chargedischarge (GCD) and electrochemical impedance spectroscopy (EIS). Electrochemical results indicate that the mole ratio of aniline to ammonium persulfate is 2∶1, exhibiting a significant improvement in the specific capacitance of 762.4 F/g at 0.5 A/g and 530.6 F/g even at 10 A/g. It maintains its capacity retention rate of 74.4% after 1000 cycles. In contrast to other samples, the optimized PANI has higher specific capacitance as well as better rate capability, suggesting its wide applications in supercapacitor.