Background: Evidence suggests that dry CO2 insufflation during laparoscopic colorectal surgery results in greater structural injury to the peritoneum and longer hospital stay than the use of warm, humidified CO2. We aimed to test the hypothesis that warm, humidified CO2 insufflation could reduce postoperative pain and improve recovery in laparoscopic colorectal surgery. Methods: One hundred fifty elderly patients undergoing laparoscopic colorectal surgery under general anesthesia from May 2017 to October 2018 were randomly divided into 3 groups. The primary outcomes were resting pain, cough pain, and consumption of sufentanil at 2, 4, 6, 12, 24, and 48 hours postoperatively. Quality of visual image, hemodynamic changes, esophageal temperature, mean skin temperature, mean body temperature, recovery time, days to first flatus and solid food intake, shivering, incidence of postoperative ileus, length of hospital stay, surgical site infections, patients and surgeon satisfaction scores, adverse events, prothrombin time, activated partial thromboplastin time, and thrombin time were recorded. Results: Group CE patients were associated with significantly higher early postoperative cough pain and sufentanil consumption than the other 2 groups (P<.05). Compared with group CE, patients in both groups WH and CF had significantly reduced intraoperative hypothermia, recovery time of PACU, days to first flatus and solid food intake, and length of hospital stay, while the satisfaction scores of both patients and surgeon were significantly higher (P<.05). Prothrombin time, activated partial thromboplastin time, and thrombin time were significantly higher in group CE from 60minutes after pneumoperitoneum to the end of pneumoperitoneum than the other 2 groups (P<.05). The number of patients with a shivering grade of 0 was significantly lower and grade of 3 was significantly higher in group CE than in the other 2 groups (P<.05). Conclusion: Use of either warm, humidified CO2 insufflations or 20 degrees C, 0% relative humidity CO2 combined with forced-air warmer set to 38 degrees C during insufflations can both reduce intraoperative hypothermia, dysfunction of coagulation, early postoperative cough pain, sufentanil consumption, days to first flatus, solid food intake, and length of hospital stay.