Objective To observe the protective effect of acupuncture-drug compound anesthesia with different frequency electroacupuncture（EA） on stress reaction in patients of pneumonectomy and to explore potential mechanisms.Methods Eighty patients scheduled for pneumonectomy were randomly divided into four groups,group A,B,C and D,20 cases in each group.General anesthesia and single lung protective mechanical ventilation were carried out in all the groups.Acupuncture was given at Hòuxī（后溪 SI 3）,Zhīgōu（支沟TE 6）,Nèiguān（内关 PC 6）,and Hégǔ（合谷 LI 4） 30 min before general anesthesia,and the acupuncture needles were connected with Han＇s acupoint nerve stimulator（HANS-200） in all the groups,but the acupuncture needles without needle bodies were pasted on the acupoints and EA was not given in the group A.2 Hz continuous wave,100 Hz continuous wave and 2 Hz/100 Hz EA were given in the group B,C and D respectively.The supplementary amount of anesthesia medicine,heart rate（HR） and mean arterial pressure（MAP） during pneumonectomy,and CD4^＋/CD8^＋ in venous blood before and one day after the surgery,and the contents of epinephrine（E） and cortisol（Cor） in plasma after entering the operating room and before turning out the operating room were detected.Results ① During the operation,supplementary amounts of Fentanyl in the group B and C were lower than those in the group A and D（P〈0.05,P〈0.01）.② The MAP in the four groups at tracheal intubation（T1） all were higher than those before anesthesia（T0）（all P〈0.01）,and the ascending extents in the group B,C and D were lower than that in the group A（all P〈0.01）;HR at T1 in the group A was higher than that at T0（P〈0.05）,while no significant change in the other groups（all P〈0.05）,and the ascending extents in the group B and D were lower than that in the group A（both P〈0.05）;MAP and HR at the other moments in all the groups were stable.③ CD4^＋/CD8^＋ in the group A after pneumon
