CdS/PANI(poly-aniline) composite film was prepared by the current impulse electrodeposition on the PANI/PATP (p-aminothiophenol)/Au. The structure and performances were characterized by means of SEM and UV-Vis, IR, Raman, fluorescence and XPS spectroscopies. The CdS nano-particles in the nano-CdS/PANI composite films show the size quantization effect and the enhanced photoluminescence effect by PANI. The photo-generated carriers transfer mechanism from PANI into nano-CdS was proposed to explain the effect. The chemical interaction between NH-groups of PANI chains and S2- ions of nano-CdS is found.