Objective To investigate the correlation between Young's modulus obtained by shear wave elastrography (SWE) and lymph node metastasis in rectal cancer. To explore the diagnostic value of SWE in T stage of rectal cancer. Methods The clinical data of 53 rectal cancer patients were retrospectively analyzed. All patients were examined with the endorectal ultrasonography (ERUS) and SWE before operation, and the average lesion Emean value was measured with the postoperative pathology as the gold standard. According to whether lymph node metastasis occurred in pelvis and peritoneal cavity, there were two groups: lymph node metastasis group (LNM) and non-lymph node metastasis group (NLNM). The correlation between SWE and LNM of rectal cancer and the accuracy of T staging were evaluated. Results There was a moderate positive correlation between LNM and Emean values (r =0.533, P < 0.001), and the difference of Emean values between LNM and NLNM was statistically significant (P < 0.001). The diagnostic accuracy of ERUS combined with SWE for T stage of rectal cancer was 86.8%, and the difference of Emean values for different T stages of rectal cancer was statistically significant (P < 0.001). Receiver operating characteristic (ROC) curve showed that the optimal staging cutoff values of T1/T2, T2/T3 and T3/T4 were 19.8, 47.1 and 141.6kPa, respectively, and the area under the curve was 0.718 ~ 1.000. Conclusion ERUS combined with SWE technique can be used as an effective method to assist the diagnosis of T stage of rectal cancer. The close correlation between Emean value and LNM of rectal cancer also proves its excellent performance in predicting the prognosis of rectal cancer.