Abstract: In this study, a fibrous activated boron nitride material with abundant pores was prepared. Its specific surface area and mesoporous pore volume were 944.526m²/g and 0.324cm³/g, respectively. At the same time, the interaction of Cu² 、Pb² and Cd² in wastewater and the adsorption behavior mechanism of activated boron nitride were explored. It was found that in single system, the adsorption capacity of activated boron nitride follows Pb² >Cd² >Cu² , but in ternary system, heavy metal ions will interact, that is, Cu² has a synergistic effect on the adsorption of Pb² , and has an antagonistic effect on the adsorption of Cd² . The adsorption of Pb² on Cd² has an antagonistic effect within 30 min, and has a synergistic effect after 30 min. On the contrary, Pb² has a synergistic effect on the adsorption of Cu² , while Cd² has an antagonistic effect on the adsorption of Cu² , and Cd² has a synergistic effect on the adsorption of Pb² . Compared with activated carbon, activated boron nitride showed stronger adsorption capacity in heavy metal solution. For heavy metals Cu² 、Pb² and Cd² , the maximum adsorption capacity of activated boron nitride was 1.32 times, 24.75 times and 20 times that of activated carbon, respectively. For the adsorption of Cu² 、Pb² and Cd² by activated boron nitride, it was found that the adsorption of Cu² 、Pb² and Cd² all conformed to the Langmuir model indicating that the adsorption process was mainly controlled by chemical adsorption. XPS was used to analyze the surface chemical state of activated boron nitride after adsorption. It was found that Cu² combined with activated boron nitride to Cu(OH)₂ and -OCu, Pb² and Cd² combine with activated boron nitride to PbCO₃, Cd(OH)₂ and CdCO₃. The adsorption mechanism of activated boron nitride includes three adsorption mechanisms: the formation of complexes between surface-NH₂ and heavy metal ions, the ion exchange between H in -OH and heavy metal ions, and the combination of B-O and heavy metal ions through electrostatic interaction.