In this work, a user-friendly chitin-based adsorbent (CT-PmPD) was synthesized by in-situ polymerization of m-phenylenediamine on the chitin bead, which could effectively remove Cr(VI) from water. The structure and morphology of the CT-PmPD were characterized by FT-IR, XRD, SEM, zeta potential and XPS. Specifically, the effect of adsorbed dosage, pH, contact time, adsorption temperature and coexisting salt on the adsorption of Cr(VI) were studied. Besides, the adsorption mechanism of CT-PmPD toward Cr(VI) were also analyzed. Consequenlty, The CT-PmPD exhibited a monolayer adsorption and the Langmuir model fitted a Cr(VI) adsorption capacity reached 185.4 mg/g at 298 K. The high adsorption capacity was attributed to the abundant amino groups of CT-PmPD, which could be protonated to boost the electrostatically attraction of Cr(VI) oxyanions, thus providing electron to reduce Cr(VI). Additionally, the CT-PmPD revealed a good regeneration and reusability capacity, which maintained most of its adsorption capacity even after five cycles of adsorption-desorption. This high adsorption capacity and excellent regeneration performance highlighted the great potential of CT-PmPD on the removal of Cr(VI).