Objective To investigate the value of dual-source CT energy imaging in the diagnosis of peripheral gastric cancer invasion. Methods We collected the complete data of 64 patients who has been diagnosed with gastric cancer in our hospital, all patients underwent dual-source CT abdominal routine scanning and energy spectrum enhancement scans. According to the pathologic results, the lymph nodes and adipose tissue were divided into metastatic and non metastatic groups, then measured and compared the difference of standardized iodine concentrations (Normalized Iodine Concentration, NIC) between the metastatic and the non metastatic of gastric cancer respectively. Results The NIC value of metastatic lymph node artery was (0.545±0.087), the non metastatic lymph node was (0.143±0.078), and the difference was statistically significant (P＜0.05). The metastatic lymph node NIC in venous period was (0.478±0.014), and the non metastatic lymph nodes were (0.306±0.083), the difference was statistically significant (P＜0.05). When the standardized iodine concentration in arterial phase was > 0.223, the sensitivity of the diagnostic lymph node was 69.8%, the specificity was 91.2%, and the diagnostic sensitivity was 78.3% and the specificity was 85.6% in the venous phase standardized iodine concentration > 0.392. The NIC values of the affected adipose tissue and the unexposed fat tissue were (0.651±0.351) and (0.001±0.180) respectively, and the differences were statistically significant (P<0.05). The NIC value of venous period was (1.081±0.429) and (0.170±0.251), and the difference was statistically significant (P<0.05). When the standardized iodine concentration in arterial phase was > 0.150, the sensitivity of invasive adipose tissue was 97.8%, the specificity was 86.7%, and the diagnostic sensitivity was 86.8% and the specificity was 98.8% in the venous phase standardized iodine concentration > 0.620. Conclusion The NIC value of energy imaging is helpful for the diagnosis of gastric cancer invasion, and can be used as a quantitative index for the prognosis evaluation of gastric cancer.