ObjectiveTo investigate the vaules of multi-slice spiral CT (MSCT) in diagnosing metastatic lymph nodes and judging N stage of resectable gastric cancer. MethodsFifty-nine patients with gastric cancer performed preoperative MSCT plain scan and triple enhanced scans from February 2019 to March 2021 in the First People’s Hospital of Wuhu City were collected. The results of postoperative pathology were taken as the gold standard, the short diameter, long diameter, short to long diameter ratio, CT values of triple enhanced scans and lymphatic hilar blur were compared between the metastatic lymph nodes and the non-metastatic lymph nodes. ResultsThe preoperative MSCT showed that there were 50 cases of metastatic lymph nodes and 9 cases of non-metastatic lymph nodes in 59 patients with gastric cancer. A total of 1 467 lymph nodes were harvested, including 562 metastatic lymph nodes and 905 non-metastatic lymph nodes. The short diameter, long diameter, short to long diameter ratio, and the CT values of plain scan, arterial phase, portal vein phase, and delayed phase of metastatic lymph nodes were higher than those of non-metastatic lymph nodes (P<0.05), and the incidence of lymphatic hilar blur was also higher than that of non-metastatic lymph nodes (P<0.05). Referring to the results of postoperative pathological examination, the accuracies of MSCT in judging of N0, N1, N2, N3a, and N3b stages were 88.9% (8/9), 83.3% (5/6), 85.7% (12/14), 92.3% (12/13), 88.2% (15/17), respectively, and the total accuracy was 88.1% (52/59), the specificity was 96.6% (57/59), and the sensitivity was 91.2% (52/57). ConclusionAccording to this study results, preoperative MSCT has higher specificity, sensitivity, and accuracy in diagnosing metastatic lymph nodes and judging N stage of resectable gastric cancer.