In order to study the effects of activated carbon on the roots growth,C and N metabolism and protective enzymes of ‘Heifeng No.1’ in Shanxi,various doses of activated carbon(0,2.5,5.0,7.5 and 10 g/kg) were added into soil in greenhouse pot.Results showed that:(1)With the concentration of activated carbon increasing,the roots growth showed an optimal performance and the average diameter showed a minimum value;Total root length,total surface areas,total volume,root active absorbing areas and the number were improved significantly (P<0.05) with 5.0 (B_5.0) and 7.5 (B_7.5) g/kg activated carbon applied,but the root grew weak with 10 g/kg activated carbon(B₁₀).(2)With the concentration of activated carbon increasing,the activity of invertase reached a peak at B_5.0,and then decreased gradually in pot culture;Invertase activity and soluble sugar content were increased significantly (P<0.01) treated by 2.5 (B_2.5) and 5.0 (B_5.0) g/kg activated carbon,and B_7.5 and B₁₀ performed similar to the control (CK).(3)With the concentration of activated carbon increasing,the activity of GS increased and then decreased gradually in culture;The activities of GS were increased significantly (P<0.01) treated by 5.0 (B_5.0) and 7.5 (B_7.5) g/kg activated carbon;and protein content at B_7.5 was improved as well.(4)With activated carbon added increasing,the activities of SOD,POD and CAT also got a maximum and then changed very little with the culture time;The activities of SOD,POD and CAT at B_2.5 were much higher than that of CK.Therefore,we concluded that certain activated carbon could improve the metabolism,activities of protective enzymes and root growth.