Objective To study the application value of endoscopic ultrasonography (EUS) in preoperative staging of colorectal cancer (CRC) and guidance of surgical procedures. Methods 52 cases of patients with CRC who were admitted in the department of colorectal surgery of our hospital from November 2014 and November 2015 were selected. All of them underwent radical resection and were confirmed by surgical and pathological observation. Surgical and pathological TNM staging results were taken as golden standard. Before surgery, endoscopic ultrasonography was performed in the selected patients. Referring to the gold standard, TNM staging diagnostic effects of endoscopic ultrasonography were retrospectively analyzed. Results The EUS diagnostic results of 52 patients with CRC showed that the accuracy rates of tumor invasion T stage (T1-T4) were 87.50%, 80.00%, 94.12% and 83.33% respectively. There was no significant difference, compared with surgical and pathological golden standard (P>0.05); The accuracy rates of EUS in diagnosis of lymph node metastasis N stage (N0-N2) were 76.92%, 79.17% and 86.67%, respectively. There was no significant difference in accuracy rate in N0 and N2, compared with the gold standard (P>0.05), but the accuracy in N1 stage was lower than that of gold standard (P<0.05). Conclusion Although ENS has some errors in the diagnosis of degree of lymph node metastasis, especially N1, on the whole, EUS can be better to observe the depth of tumor invasion and lymph node metastasis in patients with CRC. The diagnosis combining with EUS before surgery is helpful to the preoperative pathological staging, and provide reference for the selection of appropriate surgical procedures.