Peroxidase plays an important role in living systems; however, its storage difficulty and easy inactivation have limited its applications in complex environments. To address these problems, herein, we proposed a method to synthesize peroxidase mimics by amination, carbonization, and Fe³⁺-doping of industrial alkali lignin. The Fe³⁺-doped lignin-based peroxidase mimic (Fe-LPM), with active centers of coordination between Fe³⁺ and N atoms, showed higher tolerance to pH value and temperature than natural peroxidase. Using Fe-LPM, 10-100 mmol/L of H₂O₂ and glucose could be colorimetrically detected with the lowest detection limits of 80 μmol/L and 1.5 mmol/L and visual detection limits of 1.0 mmol/L and 10 mmol/L, respectively. The Fe-LPM maintained peroxidase-like activity after 10 cycles and could even be used for H₂O₂ detection in practical samples. This work not only provides a new approach to synthesize peroxidase mimics using biomass materials but also promotes the high-value utilization of lignin.