Objective To evaluate the clinical value of enhanced 128-slice spiral CT in the diagnosis of TNM staging of gastric cancer. Methods 44 patients with gastric cancer underwent 128-slice spiral CT scan from January 2012 to September 2014. The patients were diagnosed by TNM staging according to the scan results and staged with pathological TNM stage and to evaluate the clinical value of 128-slice spiral CT in the preoperative TNM staging of gastric cancer. Results The accuracy of T1 was 50.00%, the accuracy of T2 was 63.64%, the accuracy of T3 was 73.68%; the accuracy of T4 was 90.00%, the overall accuracy of T was 72.73%, the accuracy of N0 was 68.75%, the accuracy rate of N1 was 76.19%, the accuracy of N2 was 85.71% and the accuracy of N was 75.00%. The accuracy rate of M0 was 96.67%, the accuracy of M1 was 85.71% and the accuracy of M was 93.18%. There was significant difference between CT and pathological diagnosis in T stage and N stage (P<0.05), but there was no significant difference in M stage (P>0.05). Conclusion 128-slice spiral CT can accurately show the depth of stomach invasion, lymph node metastasis and metastasis of distant organs in gastric cancer. It has high accuracy in judging M staging of gastric cancer and worthy of popularization.