Objective To investigate the effect of via-anal ileus tube used as a drainage in left-sided acute malignant colonic obstruction.Methods Forty-seven cases of left-sided acute malignant colonic obstruction were divided into control group (25 cases) and tube group (22 cases).The patients in control group received intraoperative colonic lavage for one-stage surgery.The patients in tube group received via-anal ileus tube for decompression before the surgery.Compared the difference of bowel movement recovery time,exhaust time,fasting time,postoperative hospitalization time,hospitalization costs and complication rate between two groups.Results The technically successful rate in tube group was 90.9％ (20/22),and one-stage surgery were performed.No anastomotic leakage or postoperative stenosis occunred after operation.There were 23 cases in control group who performed coloclysis in operation and one-stage surgery.The bowel movement recovery time,exhaust time,fasting time,postoperative hospitalization time and hospitalization costs in tube group were significantly lower than those in control group [(12.78 ± 2.07) h vs.(18.01 ±3.42) h,(78.76 ± 11.43) h vs.(96.38 ±13.09) h,(3.18 ±1.76) d vs.(5.51 ±2.95) d,(10.23 ± 2.33) d vs.(15.86 ± 6.74) d,(25 437.43 ± 2 343.67) Yuan vs.(31 051.32 ± 2 542.73) Yuan](P ＜ 0.01 or ＜ 0.05).After operation,there were 2 cases of stomas fistula and 2 cases of peritoneal cavity infection in control group,and none of them in tube group,the complication rate in control group was significantly higher than that in tube group [17.4％ (4/23) vs.0,P ＜ 0.05].Conclusions The via-anal ileus tube used as a drainage in left-sided acute malignant colonic obstruction is effective and safe,and can improve the rate of one-stage anastomoses,decrease the complication rate,promote the promote.It has important clinical value.