To effectively improve the efficiency of plant extracting heavy metals from polluted soils, green safe organic materials were used as activating agents to replace safety hazards, non-degradable chelating agents and surfactants. The activation effects of different activating agents on soil heavy metal Cd and their effects on plant Cd accumulation were explored. The effects of three kinds of activating agents of milk vetch (MV), potassium humate (KH) and citric acid (CA) on the bioavailability and morphological characteristics of Cd in Cd-contaminated farmland soil and the accumulation of Cd by activator-fortified willay were studied by incubation and pot expriments with 0.3% application rate. The results showed that:(1) Adding an activator changed soil pH value. At the end of the culture, the effect of KH treatment on soil pH was better than that of MV, which was significantly lower than the control by 0.50 units (p<0.05), while the pH of the soil treated with CA was significantly higher than that of the control by 0.26 unit (p<0.05); Adding an activator could increase the soil organic matter content. At the end of the culture, the effect of KH treatment on the soil organic matter content was better than the other two activating agents, which was significantly higher than the control by 2.97 g/kg (p<0.05). (2) Adding activator could increase the effective Cd content of soil, but the activation effect of different activating agents was different. On the 20th day after culture, the effective Cd content of the soil treated with MV and KH reached the highest, which was better than that of CA treatment, which was higher than the control by 0.38 mg/kg (p<0.05) and 0.17 mg/kg respectively. When cultured for 10~30 days, the effective Cd content of CA treated soil increased gradually. After 30 days, the effect of CA treatment on soil effective Cd content was better than the other two activating agents, which was significantly higher than the control treatment by 0.39 mg/kg (p<0.05). (3) Adding activating agents changed the Cd form of soil. Cultured for 10~30 days, all three activating agents could activate soil residue Cd and increase the percentage of acid extractable Cd. (4) The three activating agents treatments had no significant effect on the plant height and biomass of the willow, but all increased the morphological parameters of the roots. The root length, surface area and root volume of CA treatment were significantly higher than the control, which increased by 75.54%, 80.05% and 82.93% (p<0.05) respectively. KH treatment significantly increased the Cd content in the leaves, branches and roots of the willow, which was higher than the control by 133.44% (p<0.05), 75.21% and 264.64% (p<0.05) respectively, and greatly improved enrichment and purification of Cd in soil by willow. The use of organic materials as activating agents could effectively improve the bioavailability of heavy metals in soils, and should have a good application prospect in combination with plant extraction of heavy metals.