In order to study the feasibility of Mn(Ⅱ) removal in water by alkali modified pomelo peel biochar in practical use, whose dynamic adsorption of Mn(Ⅱ) in a fixed bed was implemented. The effects on alkali modified pomelo peel biochar adsorbed Mn(Ⅱ) in a fixed bed by flow rate, bed height and Mn(Ⅱ) initial concentration were researched, and the data were fitted by varying models, the results showed that the adsorption of Mn(Ⅱ) by alkali modified pomelo peel biochar possessed a buffering action to some extent; the fixed bed operation time was prolonged with the decrease of flow rate and Mn(Ⅱ) initial concentration and increase of bed height, the highest adsorption capacity of alkali modified pomelo peel biochar for Mn(Ⅱ) was 25.59mg/g, which was obtained in flow rate was 1 mL/min, Mn(Ⅱ) initial concentration was 150mg/L and bed height was 2cm; the Thomas model indicated that internal and external diffusion weren’t control procedure in the process of adsorption; the Adams–Bohart model suggested the adsorption preliminary kinetic in the fixed bed was controlled by external mass transfer, its linear expression (the BDST model) predicted the operation time of effluent Mn(Ⅱ) concentration reach 70% of influent Mn(Ⅱ) concentration in each condition with comparatively accuracy; the modified dose-response model described the shape of the Mn(Ⅱ) breakthrough curve accurately. The research indicated that there was potential to removed Mn(Ⅱ) for alkali modified pomelo peel biochar in a fixed bed practical use.