Objective To investigate the efficacies of preoperative location with titanium clip and methylene blue staining in laparoscopic colectomy.Methods The clinical data of 31 patients with colorectal polyps which could not be resected under endoscope were admitted to the Third Affiliated Hospital of Sun Yat-Sen University from August 2006 to September 2012 were retrospectively analyzed.According to the methods of preoperative location of colorectal polyps,all patients were divided into the titanium clip group (18 patients) and the methylene blue group (13 patients).Titanium clip group:enteroscopic and pathological examination were firstly performed,and then 1 or 2 titanium clips were placed at the superior and inferior part of the polyps.After enteroscopic examination,abdominal X ray examination was performed to detect the position of polyps according to the positions of the titanium clips.Methylene blue group:after colonoscopy,methylene blue of 1 mL was injected into the adjacent mucosa of the polyps,and 4 positions around the polyps were selected for the injection of methylene blue.If the 2 locating methods were failed,intraoperative enteroscopy was performed.Laparoscopic resection for intestine or mesenterium was performed according to the treatment principle of colorectal neoplasms,and the location efficacy of the 2 methods and the treatment of the 2 groups were analyzed.The measurement data and the count data were analyzed using the t test and chi-square test,respectively.Results The success rates of the titanium clip group and the methylene blue group were 15/18 and 8/13,with no significant difference between the 2 groups (x2=0.284,P ＞0.05).The polyps in 8 patients which were failed to be localized by titanium clip or methylene blue were localized by intraoperative enteroscopy,while the operation time was prolonged to (44 ± 13)minutes.No positioning errors were detected in all the 31 patients.Laparoscopic right colectomy was performed on 4 patients,laparoscopic left colectomy on 11 patients,laparoscopic sigmoid colectomy on 9 patients,laparoscopic anterior resection of rectum on 7 patients.No morbidity or mortality was detected in the 2 groups.The length of specimen,distance between the proximal margin and the superior margin of the tumor,distance between the distal margin and the inferior margin of the tumor (patients with colonic polyps),distance between the distal margin and the inferior margin of the tumor (patients with high rectal polyps),and the number of lymph node resected were (20 ± 7) cm,(11 ± 4) cm,(8.6 ± 3.1) cm,4.2 ± 1.1,8 ± 5 in the titanium clip group,and (20 ± 5) cm,(9 ± 3) cm,(9.1 ± 2.8) cm,4.6 ± 0.5,7 ± 6 in the methylene blue group,with no significant difference between the 2 groups (t =0.053,0.918,0.213,1.486,0.267,P ＞0.05).Fifteen patients had cancerization of the polyps,including 8 patients with TNM Ⅰ stage,6 with TNM Ⅱ] stage and 1 with TNM Ⅲ stage.Conclusions For patients with colorectal polyps located at the intestine above the descending colon,titanium clip locating is easy,safe and effective,and it could be the first choice for locating the colorectal polyps.Endoscopic methvlene blue staining is simple but high technique demanding.Intraoperative enteroscopy is precise for locating the polyps at the intestine below the descending colon.