The high toxicity and mobility of hexavalent chromium (Cr­(VI)) allow it to easily spread and bioaccumulate, and its detection is a major part of environmental protection. In this work, an innovative method is developed for preparation of cerium oxide nanorod-templated metal–organic frameworks (CeO2NRs-MOF). The in situ growth of MOF on the surface of CeO2 nanorods (CeO2NRs) enhances its oxidase-like activity. In the presence of a trace amount of Cr­(VI), CeO2NRs-MOF can significantly accelerate the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) due to Cr­(VI)-boosted oxidation, resulting in a blue colored oxidation product. It can detect Cr­(VI) over a range of 0.03–5 μM with high selectivity. Moreover, this method can be applied to the detection of Cr­(VI) in different water environment samples with satisfactory recoveries, demonstrating the potential application of CeO2NRs-MOF for the direct monitoring of Cr­(VI) in environmental water systems. Thus, this work provides a facile host-templated MOF preparation method, which could possibly be extended to other fields.