Abstract: Metallic nanomaterial artificial enzymes have been studied and applied in the field of biocatalysis and biosensing due to their high peroxidase-like activity, stability, and low preparation cost. In this study, melon peel was dissolved and dispersed in a imidazolium Co-based salicylate ionic liquid to obtain a homogeneous slurry. Cobalt-biomass carbon nanocomposite artificial enzymes were synthesized after the high-temperature pyrolysis of the resultant solid from the above slurry by freeze-drying. The results show that the cobalt-biomass carbon nanocomposites (ca. 50 nm in diameter) has excellent dispersibility and distribute on the surface of biomass carbon sheets, which exhibit high peroxidase-like activity. Based on the inhibitory effect of chlorphoxim on the activity of cobalt-biomass carbon artificial enzymes, a colorimetric detection method for chlorphoxim was proposed. As chlorphoxim can inhibit the activity of cobalt-biomass carbon artificial enzymes in catalyzing the oxidation of 3,3’,5,5’-Tetramethylbenzidine (TMB), the yield of corresponding blue product is declined, presented as decreased absorbance. The absorbance of the reaction system decreases linearly with the increased chlorphoxim concentration when ranging from 0.5 to 50 μmol·L⁻¹, and the detection limit is 40 nmol·L⁻¹. The detection method is simple and rapid, which can be used for the fast determination of chlorphoxim residues in soil.