Abstract： Objective To study whether injecting methylene blue into the inferior mesenteric artery(IMA)in the redical operation of T2 stage rectal cancer can harvest more lymph nodes than the conventional method.Methods From December 2004 to June 2011,43 specimens of T2 stage colorectal cancer were studied,including 23 cases of conventional method group(using the naked eye and douching specimens to get lymph nodes)in December 2004 to August 2008,and 20 cases of methylene blue injection group(injecting methylene blue into the interior mesenteric artery combined with the conventional method)in September 2008 to June 2011.Results The average lymph nodes of each patient in the methylene blue injection group were(24 ± 14)pieces,significantly more than the conventional method group(P ＜ 0.01); and the lymph nodes of ＜ 5 mm diameter was also significantly more than that in the conventional method group(P ＜ 0.01); but the average positive lymph nodes of two groups were (1.1 ± 1.0)pieces and(0.7 ± 0.6)pieces,and the difference was not statistically significant(P ＞ 0.05).Conclusion In T2 stage rectal cancer,the method of injecting methylene blue into the inferior mesenteric artery can find out many lymph nodes,and may improve the accuracy of the postoperative staging,accordingly provides the basis for the postoperative adjuvant therapy.