Abstract: To study and analyze the value of dual-source dual-energy CT iodine determination in preoperative T staging of gastric cancer. Methods: A total of 110 patients with gastric cancer who underwent dual-source dual-energy CT examination in our hospital from January 2015 to December 2017 and confirmed by surgical pathology were enrolled. The T1 and T2-3 phases were calculated. Normalized iodine concentration (NIC) in the inner and outer layers of the gastric wall and the normal stomach wall during arterial and venous phases, and objective and subjective indicators of image quality at 40keV, 60keV, and 120keV. Results: There was a statistically significant difference between the inner and outer layers of the gastric wall and the normal stomach wall in the T-stage of the lower and middle venous stages (P<0.05). There was no significant difference between the outer layer of the gastric wall and the normal stomach wall during the arteriovenous period (P>0.05). The objective values of CT value, image noise, SNR and CNR image quality in the 120keV group were lower than those in the 60keV group and the 40keV group (P<0.05). The objective quality indicators of the 60keV group were lower than the 40keV group (P<0.05). The overall image quality score of the 60keV group was higher than that of the 40keV group and the 120keV group (P<0.05). There were no significant differences in the significant scores of the three groups (P>0.05). Conclusion: The dual-source dual-energy CT iodine value method is of great value for the differential diagnosis of T1 and T2-3 gastric cancer, and can improve the image quality, which is of great significance for enhancing the accuracy of preoperative T staging of gastric cancer. Has a good clinical application value.