Photoelectric property of polyaniline doped with dodecyl-benzene increases obviously,when polyaniline doped with DBSA is irradiated with light ,Mixture of sensitive material is advantageous to the absorption of polyaniline in visible light spectrum,and the conductivity is also improved.The results of dielectric measurements on polyaniline doped with DBSA in an Al-PAn-DBSA-Al configuration as function of frequency and temperature are reported.The space-charge polarization phenomenon is observed.Carrier lifetime is microsecond magnitude and mobility is(0.001-0.1)cm^2/V·s,which are obtained by calculation or experiment.The active energy is obtained from the relation between conductivity and temperature.The conducting mechanism of PAn-DBSA is analyzed.