To examine the differences in surface charge and functional groups of root tips and non root tips of plants and their effects on Mn(II) sorption onto plant roots, the fresh roots of maize and soybean were obtained by sand culture experiment and were divided into root tips and non root tips, and then their zeta potentials and functional groups were determined by streaming potential and ATR-FTIR, respectively. The roots were reacted with Mn(II) solution, and then exchangeable, complexed, and precipitated forms of Mn(II) sorbed on plant roots were extracted with KNO₃, EDTA-2Na and HCl sequentially. The results showed that zeta potentials of root tips of the two crops were more negative than those of the non root tips, and the root tips of the two crops carried more functional groups than the non root tips. Mn(II) sorbed on the root surfaces of two crops mainly existed as exchangeable form, and the amounts of exchangeable Mn(II) and total sorbed Mn(II) on the root tips were signi?cantly greater than these on the non root tips. The higher negative charge and the larger number of functional groups on the root tips were responsible for their higher adsorption capacity and greater binding strength for Mn(II) than the non root tips. Therefore, surface charges and functional groups play an important role in the sorption of Mn on crop roots.