Abstract In this study, heterostructured nanoparticles based on lanthanide double perovskite halide are innovatively proposed, which dramatically improved quantum yield and color purity, but the problem of water stability of perovskite materials has also been solved. The nanoparticles without surface ligands have excellent stability and optical properties when dispersed in water, and have higher color purity than those dispersed in organic solvents. Besides, the application potential is demonstrated and the practical performance is verified by preparing luminescent ink. This study provides a new strategy for the performance enhancement and application prospect of lanthanide double perovskite.