The peroxidase-like nitrogen-doped carbon dots were synthesized using ethylenediaminetetraacetic acid as both carbon and nitrogen sources. In a typical experiment, 300 mg ethylenediaminetetraacetic acid was directly heated at 400 ℃ for about 2 hours. Afterward, the CDs were dissolved in acetone and centrifuged to remove the residual solid particles. The solvent was then evaporated and the results CDs were collected and dissolved in water for next use.