Developing efficient electrocatalyst at large current densities to meet the requirement of industrial water splitting is a big challenge today. Herein, we report a class of catalyst, BiCoO3 with pyramidally coordinated Co3+. BiCoO3 exhibits a large current density of 1000 mA cm−2 at a low overpotential of 402 mV and the overpotential even reduces to only 303 mV to achieve 1000 mA cm−2 by replacing Co with Fe, which belongs to the first-class level among large-current-densities electrocatalysts reported so far. Different from artificially created oxygen vacancies to optimize the bonding strength of the intermediate for enhancement of OER activity, BiCoO3 has the rich active sites and the shortest reaction pathway leading to a large current density, as structurally every Co-O cluster has one oxygen vacancy. This work opens a new avenue for enhanced OER activity at high current densities via optimizing the arrangement of ligand vacancies.