Polybithiophene (PBTh) films electropolymerized at different current densities were used as hole-transport layer in the electroluminescent (EL) devices. It was found that the current density used for depositing PBTh film greatly affects the surface structure of the film, which determines the effectiveness of the PBTh film as the hole-transport layer used in the EL device on enhancing EL intensity and efficiency. Evidences show that for a high effective EL device there is an optimal current density for depositing the PBTh films as the hole-transport layer.