Abstarct: In this study, biochar magnetic nanocomposite (BC-MNP) was synthesized as a strong adsorbent to remove the toxic heavy mextal Pb(II) from aqueous solution. And its physical and chemical properties were analyzed using SEM, FTIR, XRD and BET analyses. In order to study the effect of operational parameters such as solution pH, concentration of lead ions, amount of adsorbent and contact time on the efficiency of removal of lead ions, experimental design with response surface method (RSM) was used. The results showed that the removal efficiency of lead (II) by BC-MNP in optimal conditions (pH = 7, amount of adsorbent 0.24 g/L, initial concentration of lead (II) 30 mg/L and contact time 15 minutes), 93.47 And its maximum absorption capacity is 504 mg/g. Isotherm and kinetic studies showed that the adsorption process follows the Langmuir isotherm model and pseudo-second-order kinetics. Thermodynamic data also showed that the absorption process is possible, spontaneous and endothermic. Also, the efficiency and reusability of BC-MNP adsorbent in lead removal was also investigated and the results showed that after three absorption/desorption cycles, its efficiency is more than 80%. In addition to the high efficiency of this adsorbent in removing lead heavy mextal, due to its magnetic property, it can be well separated from the aqueous solution with an external magnetic field.