Electrochemical water splitting is one of the most promising techniques for producing high-purity hydrogen without carbon emissions. To commercialize this attractive technique, designing cost-effective, highly efficient, and stable electrocatalysts is desired. Perovskite oxides have been widely applied in many fields as efficient and low-cost catalysts due to their flexible compositions and structures, offering considerable opportunities and strategies to design desired electrocatalysts. In this Review, we present emerging strategies mainly based on our group's works about electrochemical water splitting for developing perovskite-based electrocatalysts to enhance the intrinsic and apparent activity of water splitting. The relationship between the composition/structure and the electrochemical activity of these materials is established for the rational design of more practical water-splitting electrocatalysts.