Objective: Detect lead ions in water using Fe3O4@C/\[BSMIM\]HSO4/GCE. Methods: The Fe3O4@C that had core-shell structure was synthesized based on Fe3O4 which was compounded with 1-methyl-3-butanesulphonic acid imidazole bisulfate ionic liquid for preparing the Fe3O4@C/\[BSMIM\]HSO4 sensor that using the glassy carbon electrode as carrier. Results: The study found that Fe3O4@C had a good conductivity and dispersion. The Fe3O4@C/\[BSMIM\]HSO4/GCE has a good electrochemical stability and electrocatalytic activity. The quantitative analysis of lead ion in drinking water was done using the Fe3O4@C/\[BSMIM\]HSO4/GCE. The result showed that there was a good linear relationship between the concentration of lead ion and its oxidation peak current in the range of 0.1～80.0 μg/L, R2=0.999 5, the detection limit was 0.038 μg/L(S/N=3), which was very low, and the recovery was 97.60%～100.93%, with very good recovery effect and high accuracy. The sensor has a good repeatability, the RSD for 10 times was 2.446%. Conclusion: The method is simple, fast and reliable, which provides a new solution for the detecting the lead ions in drinking water.