Objective To observe the application effect of general anesthesia (GA) combined with ropivacaine transversus abdominis nerve block (TANB) in radical resection of colorectal cancer. Method This study is a retrospective analysis. 68 patients with colorectal cancer undergoing radical resection in Jianhu County People's Hospital of Yancheng City from March 2022 to December 2024 were selected and divided into control group and study group, 34 cases in each group according to the difference of anesthesia methods. The control group was given general anesthesia, and the study group was given GA+ ropivacaine TANB. The anesthesia effect, pain, drug use and adverse reactions of the two groups at different time points were compared. Result Before anesthesia induction (T0), there was no significant difference in heart rate, mean arterial pressure, epinephrine and norepinephrine levels between the two groups (P > 0.05). From T1 to T3, the heart rate, mean arterial pressure, epinephrine and norepinephrine levels in the study group were lower than those in the control group, and the differences were significant (P < 0.001). At 1h, 6h, 12h and 24h after operation, the visual analogue scale scores of the study group were lower than those of the control group, and the differences were significant (P < 0.01). There was no significant difference in the recovery time, extubation time and recovery time of spontaneous breathing between the two groups (P > 0.05), but the dosage of remifentanil and propofol in the study group was less than that in the control group, and the difference was significant (P < 0.05). The study group had 1 case of nausea and vomiting, 1 case of respiratory depression and 1 case of urinary retention, no postoperative delirium, and the incidence of adverse reactions was 8.82%(3/34). The control group had 5 cases of nausea and vomiting, 2 cases of respiratory depression, 2 cases of urinary retention, and 1 case of postoperative delirium, and the incidence of adverse reactions was 29.41% (10/34). There was a significant difference in the incidence of adverse reactions between the two groups (χ2=4.660, P=0.031). Conclusion The application of GA combined with ropivacaine TANB in patients undergoing radical resection of colorectal cancer can maintain good basic signs, reduce stress reaction, reduce the use of intraoperative anesthetics, and reduce postoperative adverse reactions and pain.