Abstract: Objective To investigate the effect of laparoscopic radical resection of rectal cancer by reserving the left colon artery and root lymph node accurately according to different types of inferior mesenteric artery. Methods In this study,80 cases of rectal cancer patients diagnosed and treated from January 2019 to January 2022 were selected as the research objects.According to the envelope random grouping method,the above patients were randomly divided into observation group and control group,with 40 cases in each group.According to the intestinal mesenteric classification of patients,the observation group carried out precise low ligation operation,while the control group adopted traditional high ligation operation.The perioperative indexes,complications,gastrointestinal function,gastrin and motilin were compared between the two groups. Result There was no significant difference in operation time,intraoperative blood loss,exhaust time and lymph node positive rate between the two groups (P>0.05),and the number of lymph node dissection in the observation group (24.27±5.92) was significantly higher than that in the control group (16.12±5.99)，there was significant difference (P＜0.05).There was no significant difference in dysuria,anastomotic bleeding and anastomotic leakage between the two groups (P>0.05). There was no significant difference between the recovery time of bowel sounds and the time of eating (P>0.05).After operation,the gastrin and motilin water in the two groups decreased significantly,but the gastrin[(133.33±16.14)pg/ml] and motilin(318.33±24.11) pg/ml] in the observation group were significantly higher than that of the control group[(114.78±15.97) pg/ml,(287.44±23.09)pg/ml]，the difference was statistically significant(P＜0.05). Conclusion Laparoscopic radical resection of rectal cancer according to the different types of inferior mesenteric artery accurately retain the left colon artery and root lymph node dissection,postoperative gastrointestinal function and lymph node dissection significantly improved,for the prognosis of patients with positive significance.

Key words: laparoscopic, rectal cancer, left colon artery preservation, root lymph node dissection