Ｏｂｊｅｃｔｉｖｅ　To investigate effects of patient-controlled analgesia (PCA) with dexmedetomidine(Dex) on recovery of intestinal function and inflammatory response after radical colectomy in colon cancer patients.　Methods　Ninety colon cancer patients subjected to radical colectomy were enrolled in this study. They were randomly divided into 3 groups (n=30): patient-controlled analgesia with Dex+sufentanil+granisetron (group A), patient-controlled analgesia with sufentanil+granisetron (group B), bucinperazine (a painkiller) injection group (group C). For all groups, postoperative analgesia lasted for 3 days during which VAS scores (pain) and Ramsay scores (sedation) were calculated and venous plasma was extracted to examine the levels of TNF-α and IL-6, 12 h(T1), 24 h(T2) and 48 h(T3) after surgery. Anus exhaust time was also recorded.　Results　Compared with group C, both group A and B exhibited lower pain scores and higher sedation scores(P<0.05) after surgery. Although group A and B had no significant difference in VAS scores after surgery(P>0.05), group A showed higher sedation scores (P<0.05). Levels of TNF-α and IL-6 in venous plasma were lower in group A than those in Group B and C(P<0.05). Anus exhaust times in group B were much longer than those in group A and group C(P<0.05).　Conclusions　The combination of Dex and sufentanil for postoperative analgesia achieved optimal anti-nociceptive and sedative effects, but reduced inflammatory responses. Meanwhile, it accelerated the recovery of intestinal function after radical colectomy in colon cancer patients.