Interfacial barrier is a key factor that determines the performances of heterojunctions.In this work,we study the effect of manganite film thickness on the effective interfacial barrier for La 0.67 Sr 0.33 MnO 3 /Nb:SrTiO 3 junctions.The barrier is extracted from the forward current-voltage characteristics.Our results demonstrate that the barrier decreases gradually from ～0.85 eV to ～0.60 eV when the film thickness decreases from 150 nm to 2 nm.The overall value of the barrier is only about 50% of the corresponding one determined from the photovoltaic effect. Interfacial barrier is a key factor that determines the performances of heterojunctions. In this work, we study the effect of manganite film thickness on the effective interfacial barrier for La 0.67 Sr 0.33 MnO 3 / Nb: SrTiO 3 junctions. The barrier is extracted from the forward current-voltage characteristics. Our results demonstrate that the barrier decreases gradually from ~ 0.85 eV to ~ 0.60 eV when the film thickness decreases from 150 nm to 2 nm. The overall value of the barrier is only about 50% of the corresponding first from the photovoltaic effect.