Lattice disorder has emerged as a novel strategy to realize visible-light photocatalytic activity, but many existing studies often involved reduction states simultaneously. Photocatalysts based on only the lattice disorder but without the reduction states are still quite lacking and challenging. To this end, we explored a new type of lattice disorder in terms of the surface atom nonstoichiometry strategy in BaTiO₃. Well-dispersed tetragonal BaTiO₃ nanocrystals with a uniform size (∼20 nm) and cuboid morphology were hydrothermally synthesized through controlling over t-butylamine and oleic acid. HRTEM coupled with structural evolution analysis reveals the existence of a Ti-rich layer on BaTiO₃ nanocrystals with surface atom disorder, which gives an overall Ti/Ba ratio of 1.50:1. This is mainly dominated by the oriented adsorption between oleic acid and surface Ba²⁺ of the nucleus during solution reaction. Such a surface disorder and Ti-rich nonstoichiometry effect could facilitate the enhanced visible-light absorption with a wavelength span of 400–700 nm that enables the superior visible-light photocatalytic property, which is not subject to the reduction states. This work demonstrates a first white material presenting a new type of lattice disorder that would be helpful for a wide range of photocatalyst explorations.