Two kinds of materials including corn stalks and diary manure were used to produce the biochars (BC and DMBC) by pyrolysing at temperature of 500ºC under the protection of nitrogen atmosphere. The single and competitive adsorption characteristics of Cu²⁺, Pb²⁺, Ni²⁺ and Cd²⁺ ions onto these biochars were investigated to reveal the interaction among the metal ions on the biochar. Experimental results show that the biochars have different elemental composition. BC has a larger specific surface area, and DMBC has a bigger average pore diameter. For the single metal adsorption, the kinetics on BC are similar, but obvious differences of adsorption rates were observed on DMBC. Langmuir isotherm model well fits the sorption data of the four metal ions, and the order of sorption capacity is Pb²⁺>Cu²⁺>Cd²⁺>Ni²⁺. Through the competitive adsorption experiments it is found that the competitive sorption capacity of Pb²⁺ is the strongest, and Cu²⁺ follows, while the sorption of Ni²⁺ and Cd²⁺ are weaker and easy to be suppressed by other divalent metal ions.