The sorption of Mn²⁺ onto walnut shell is investigated by batch experiments. The recycle of walnut shell as main agriculture and forestry wastes in the wastewater treatment is estimated. The effects of factors, including soil/water ratio, sorption time, initial concentration of Mn²⁺, and pH value on the sorption of Mn²⁺ onto walnut shell are carried out. Furthermore, the dynamics and thermodynamics of the sorption are discussed. The results show that the optimal ratio of soil (g) to water (L) is 50:1. And the optimal sorption time is 90min. When the initial concentration of Mn²⁺ is in the range of 0.32mg/L-2.17mg/L, the removal rate of Mn²⁺ in water increases with increasing initial concentration of Mn²⁺. Above 80% of Mn²⁺ is sorbed onto walnut shell, when pH value is between 7 and 9. The sorption of Mn²⁺ onto walnut shell fits in pseudo-second-order kinetics equation. The fact suggests that the initial sorption is controlled by interfacial diffusion, following by intraparticle diffusion. In addition, the sorption of Mn²⁺ onto walnut shell fits better with Freundlich equation with higher R² value. For the Freundlich constant, 1/n is less than 1. It is indicated that the sorption energy decreases with increasing initial concentration of Mn²⁺. The sorption of Mn²⁺ onto walnut shell likely occurs. In general, the walnut shell is a cost-efficient sorbent for Mn²⁺.