Biochar plays important roles in the retention of heavy metals and organic contaminants in soil. However, little attention has been paid to the factors that affect the sorption of heavy metals to biochar. Environmental factors influencing on the sorption of copper to wheat and maize-straw-derived biochars pyrolysis at different temperatures were analyzed in aqueous solution. The results showed that, biochar was an effective sorbent to retain Cu2+, and the retained Cu2+ was not easy to be desorbed. The amount of Cu2+ adsorbed increased as the increasing of pH and initial concentration of Cu2+ in solution. As the solution ionic strength increase, sorption amount of Cu2+ to high temperature produced biochar increased. Small molecular organic ligand like citric acid?suppressed the sorption, but humic acid slightly enhanced the sorption of Cu2+ to low temperature produced biochar. However, the ash content of biochar has no significant effect on the sorption of Cu2+.