Herein, inspired by the specific detection of the commercial dithizone to Zn2+, a series of polyacylhydrazones (PAHZs) with polymerization-induced emission (PIE) properties are successfully prepared and applied to the specific recognition and detection of Zn2+. It is found that all selected monomers do not emit fluorescence. In contrast, the as-prepared PAHZs can emit strong fluorescence at 455 nm, due to the intramolecular aggregation of acylhydrazone groups along the macromolecular chains, indicating a significant PIE effect. As it is expected, the PAHZs can specifically recognize and detect Zn2+ ions from 17 metal ions by the significantly enhanced fluorescence with a lower limit of detection (LOD) of 66 nM. Additionally, the complexation ratio of 2:1 between the repeating units in PAHZs and Zn2+, the coordination of Zn2+ with N and O atoms on acylhydrazone groups, and the fluorescence enhancement induced via intramolecular proton transfer are confirmed by 1H NMR and FT-IR measurements. In conclusion, the successful preparation of PIE-active PAHZs and the specific detection of Zn2+ ions provide a useful reference for the molecular design of new functional materials on the base of the traditional detection methods.