AbstractThe dynamic process of photodoping effect in the heterojunction of La0.9Sr0.1MnO3/SrNb0.01Ti0.99O3 is revealed theoretically. By solving Poisson Equation and time‐dependent carrier continuity equations, the evolutions of the carrier concentrations and the electrical potential are obtained self‐consistently. The calculated photovoltage evolution agrees well with the experimental data. The present results demonstrate that the large variation of carrier concentration mainly locates in the space‐charge region of the oxide heterojunction. It means that the photodoping effect mainly occurs in the space‐charge region of heterojunction. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)