Objective To observe the clinical value of multi-slice spiral CT (MSCT) in the diagnosis of gastric cancer.Methods The clinical data of 200 patients with gastric cancer diagnosed by pathology from February 1, 2015 to May 10, 2016 in our hospital were retrospectively analyzed, and they were divided into the observation group and the control group according to different examination methods, with 100 cases in each group. The observation group was diagnosed with MSCT, and the control group was examined with electronic gastroscopy. The detection rate, missed diagnosis rate,pathological stage detection rate, and inspection time of the two groups were compared. Results The detection rate of the observation group was higher than that of the control group, and the missed diagnosis rate of the observation group was lower than that of the control group, the differences were statistically significant (P＜0.05). The detection rate of pathological stages in the observation group was higher than that in the control group, the difference was statistically significant (P＜0.05). The observation time of the observation group was shorter than that of the control group, the difference was statistically significant (P＜0.05). Conclusion The implementation of MSCT in the diagnosis of gastric cancer patients can improve the diagnostic coincidence rate and reduce the missed diagnosis rate, which is worthy of promotion and application in clinical practice.