Strontium iridate perovskites are alternative electrocatalysts for oxygen evolution reaction (OER) in acidic media. Nevertheless, their practical feasibility is still hindered by structural stability due to the inevitable Sr leaching during long-term electrocatalysis. Herein, we propose a 0D/2D heterostructure involving CeO2 quantum dots decorated SrIrO3 nanosheets to achieve durable and active OER in harsh acidic environment. Theoretical calculations unveil that CeO2 coupling with electronic rearrangement not only lowers the energy barrier of OER but also mitigates Sr leaching. Benefiting from the activation and stabilization dual-effect of CeO2 coupling, the 4CeO(2)@SrIrO3 heterostructure exhibits an ultralow overpotential of 238 mV at 10 mA cm(-2) and a good durability for 50 h, surpassing most perovskite-related electrocatalysts in acidic media. For acidic water splitting, the water electrolyzer assembled with 4CeO(2)@SrIrO3||Pt-C coupled electrode demonstrates high activity and longlasting life. This protocol highlights an elegant approach of engineering heterostructure for robust and efficient electrocatalysis.