Excessive phosphorus discharge is one of the primary factors contributing to water eutrophication, making the development of efficient and cost-effective technologies for phosphorus-containing wastewater treatment crucial for water environment protection. In this study, bamboo biochar (BC) was prepared through pyrolysis using moso bamboo as the raw material, and manganese ferrite-modified biochar (MnFe2O4/Biochar, MB) was synthesized via a hydrothermal method for the removal of phosphate (H2PO42-) from wastewater. The effects of factors such as pH, adsorption time, and initial concentration on the adsorption performance were investigated. The results indicated that the adsorption capacity of MB for phosphate decreased with increasing pH, reaching a maximum capacity of 4.59 mg/g at pH=4.0. The adsorption process followed the Freundlich isotherm model and the pseudo-second-order kinetic model. The high saturation magnetization value of MB (48.28 emu/g) demonstrated its ease of separation. Characterization results revealed that the adsorption mechanism primarily involved the exchange of hydroxyl groups in Mn-OH with phosphate to form inner-sphere complexes. Furthermore, in actual water bodies, the presence of coexisting ions and organic matter interacted with phosphate, providing additional adsorption sites for MB and resulting in favorable phosphate removal performance. The findings of this study suggest that MB, as an efficient and easily separable adsorbent, holds significant potential for application in the treatment of phosphorus-containing wastewater.