Heavy metal Cr (VI) is one of the main sources of water pollution. In order to enhance the utilization level of landscape waste resources and search for new carbon-based adsorbent materials, boxwood branch biochar was prepared and its adsorption mechanism for Cr(Ⅵ) in aqueous solutions was investigated. Batch adsorption experiments were conducted to study the effects of initial pH, adsorption temperature and adsorption time on the biochar adsorption of Cr(Ⅵ). The adsorption mechanisms were analyzed by the characterization methods such as BET-N2, SEM-EDS, FTIR and XPS, along with the analysis of changes in Cr(Ⅵ) valence states before and after adsorption. Results indicate that the optimal pH value for Cr(Ⅵ) removal using boxwood branch biochar is 2, the most favorable adsorption temperature is 55 ℃, and an adsorption time of 3.0 hours leads to a Cr(Ⅵ) removal efficiency of nearly 100%. Chemisorption is the predominant adsorption mode, with the mechanisms primarily involving oxidation-reduction reactions, complexation and electrostatic interactions. Boxwood branch biochar produced via low-temperature pyrolysis represents a novel and highly efficient carbon-based adsorbent material. It can not only elevate the resource recycling rate of landscape waste but also offer a viable solution for the treatment of heavy metal Cr(Ⅵ).