Abstract: Biochar has a great retention potential on metal ions and has been widely used to remove heavy metals from surface runoff and groundwater. In this study, wood charcoal and bamboo charcoal with particle size of 0.80 mm were used, and the column experiments were conducted to investigate V⁵⁺ and V⁴⁺ leaching in the two types of biochar columns. The effects of vanadium valence state, initial vanadium concentration, solution pH, types and concentrations of organic acids on vanadium migration were studied. The results indicate that the retention efficiency of V⁵⁺ in the wood charcoal and bamboo charcoal columns was low, while the retention efficiency of V⁴⁺ was high in both types of columns. When the injection amount was three times of PV (pore volume, 60 mL), the effluent ratios (the ratio of effluent concentration to inlet concentration) of different initial V⁵⁺ concentrations exceeded 0.90 in both types of biochar columns, indicating that V⁵⁺ had a high migration rate in biochar columns and the influence of initial V⁵⁺ concentration on retention was not significant. When the injection amount was 8 times of PV, the effluent ratio for the V⁴⁺ solution with an initial concentration of 5 mg·L^-1 was about 0.90, whereas the effluent ratio for the V⁴⁺ solution with an initial concentration of 40 mg·L^-1 decreased to below 0.63. This suggests that the migration rate of V⁴⁺ in biochar columns had significantly decreased with the initial V⁴⁺ concentration increased. With the increase in leachate pH, the retention rates of V⁵⁺ and V⁴⁺ in both types of charcoal columns decreased, subsequently leading to an increase in the effluent ratios of V⁵⁺ and V⁴⁺ solutions. At the leachate pH of 5.5, the maximum effluent ratios for V⁵⁺ and V⁴⁺ in the wood charcoal column were 0.88 and 0.58, respectively, while they were 0.83 and 0.53 in the bamboo charcoal column. When different concentrations of oxalic acid and citric acid were added into the leachate, it was observed that high concentration organic acid promoted V⁵⁺ leaching, whereas low concentration organic acid inhibited V⁵⁺ leaching. Compared to oxalic acid, citric acid had exhibited stronger effect in inhibiting V⁵⁺ leaching in both the two types of biochar columns. Fourier-transform infrared spectroscopy (FTIR) analysis had revealed that the surfaces of biochar were predominantly characterized by acidic oxygen-containing functional groups, such as carboxyl groups, carbonyl groups, hydroxyl groups, and other functional groups, which readily formed the complexes and facilitated the deposition of V⁵⁺ and V⁴⁺. Under the condition of low pH value of the solution, the content of these acidic oxygen-containing functional groups on the biochar surface had increased, thereby significantly promoting the adsorption of V⁵⁺ and V⁴⁺ on biochar.