Objective To investigate the clinical effect of application of dezocine combined with sufentanil in patients under‐going thoracic surgery ,and discuss its security .Methods Selected 60 cases of patients undergoing thoracic surgery treatedn in the hospital from January to June 2013 ,then divided into two groups with 30 cases in each group randomly .ASA grade Ⅰ - Ⅱ ,the ob‐servation group took dezocine combined with sufentanil after the surgery ,the control group took sufentanil for analgesia ,then ob‐served the analgesia and sedative effect and the occurrence rate of adverse reaction between two groups of patients .Results The observation group′VAS pain score on postoperative 6 ,12 ,24 ,48 h were (3 .21 ± 0 .76)% ,(3 .01 ± 0 .77)% ,(2 .79 ± 0 .69)% , (2 .67 ± 0 .66)% and significantly better than the control group(P<0 .05);The observation group′Ramsay sedation score on post‐operative 6 ,12 ,24 ,48 h were (2 .12 ± 0 .23)% ,(2 .07 ± 0 .22)% ,(2 .02 ± 0 .24)% ,(2 .01 ± 0 .21)% ,the sedative effect was better than the control group(P<0 .05);48 h after the surgery the pressing times and effective analgesia pump frequency and adverse re‐action of the patients in the observation group were lower than that of the control group(P<0 .05) .Conclusion The effect for se‐dation and analgesia of dezocine combined with sufentanil in patients undergoing thoracic surgery is better and safe .