The sorption capacity of DEP onto soils increased with soil OC content and rates of biochar addition. It is generally accepted that the higher adsorption capacity of DEP to biochar reduces the bioavailability of DEP commonly released to agriculture soils during vegetable cultivation and other management practices. The amount of DEP adsorbed onto the biochar-amended soil decreased after different aging processes with the adsorption capacity of biochar-amended soil following the order of without aging > aged with constantly moist > aged with alternating wet and dry. The low OC soil amended with 0.5% biochar showed the highest adsorption capacity and weakest desorption capacity. A decreased number of effective sorption sites of biochar for DEP adsorption by high soil DOC may explain why the high OC soil with 0.5% biochar had lower adsorption compared with the low OC soil with the same treatment. The application of biochars to DEP-contaminated soils may thus be expected to change many ecotoxicological processes of DEP, thereby reducing both bioavailability and subsequent risk of entering the food chain. However, how the different aging processes affect the characteristics of biochar could not be ascertained. Therefore, more work is needed to investigate the mechanisms on how different aging conditions changes biochar properties and their impact on sorption and desorption behavior of DEP.