Injectable self‐healing hydrogels have found broad applications in drug delivery, tissue engineering and controlled 3D cell culture. In this article, the coordination interaction between polymer‐bearing imidazole groups and Mg2+ ions “trapped” in Laponite, has been employed to develop an injectable self‐healing nanocomposite hydrogel. The properties and gelation mechanism of the hydrogel have been characterized and demonstrated by rheology, TEM, XRD, SEM, and NMR in particular. The hydrogel exhibits swift self‐healing performance without waiting for long time or elevated temperature. In particular, the present hydrogel can be applied in harsh alkaline environments, exhibiting a great advantage over traditional metal ion crosslinked hydrogels. The injectable self‐healing hydrogels based on the coordination interaction between Laponite and polymer have been rarely reported. Our research may make contributions not only to the design but also to the potential application of the hydrogels in a range of harsh alkaline environments, especially in enhanced oil recovery (EOR).