Vitamin C (VC) maintains the activity of sulfhydrylase and the reduced state of glutathione, and acts as a detoxifying agent. It is widely found in plant tissues as well as in fresh fruits and vegetables. Accurate determination of vitamin C content is of great significance for diet and health care. In this work, MnO ₂ nanoflakes as the biomimetic oxidase was used to react with VC and TMB was used as a chromogenic agent. The color of the final solution reflects the concentration of VC. And the bionic E-eye as a portable in-situ detection platform was designed to analyzed the color change in 10 s by photographing. By optimizing experimental conditions, the linear range of this method for VC detection is from 7.8 μM to 62.5 μM and the detection limit 7.65 μM which is much lower than other methods. Besides, this methods shows good selectivity, short reaction time (10 min) and also was used for VC detection in artificial urine samples, which shows great potential in disease monitoring.