alpha-Fe2O3 is narrow bandgap photocatalyst that is widely used for organic-pollutant photodegradation and photoelectrochemical conversion. However, alpha-Fe2O3 with short mean-free path exhibits low photocatalytic activity due to the high recombination rate of photoexcited carriers. Accordingly, the importance of controlling particle size to reduce the recombination rate of alpha-Fe2O3 is increasingly being recognized. In this study, UiO-66 with various pore diameters was employed to confine alpha-Fe2O3 growth. The alpha-Fe2O3 nanoclusters were encapsulated inside the UiO-66 cage through simple adsorption and thermal conversion. The structure and state of alpha-Fe2O3@UiO-66 were studied by SEM, TEM and XPS analyses. Results showed that alpha-Fe2O3@UiO-66 had significantly improved photodegradation efficiency for methylene blue under visible-light irradiation due to the confining effect on alpha-Fe2O3 nanoclusters and the synergistic effect between UiO-66 and alpha-Fe2O3.