Abstract: Objective: To explore the differential diagnosis effect of energy spectrum on the pathological type of esophagogastric junction cancer. Methods: We retrospectively analyzed the clinical data of 116 patients with esophageal and gastric adenocarcinoma who were admitted to our hospital between January 2015 and January 2018. Of these patients, 64 were adenocarcinomas and 52 patients were squamous cell carcinomas. There were 27 well-differentiated cases, 45 moderately differentiated and 44 poorly differentiated. All patients underwent spectral CT scans. The ROI iodine concentration (IC), effective atomic number (Eff-Z), water concentration (WC), energy spectrum curve slope (λ_HU) in arterial and venous masses were compared between adenocarcinoma and squamous cell carcinoma patients, and the degree of differentiation was compared. In patients with arterial and venous masses, IC, Eff-Z, WC, and λ_HU. Analyze the differential diagnosis efficacy of energy spectrum CT on the pathological type and differentiation of esophageal and gastric junction cancer. Results: The comparison of IC, Eff-Z, WC, and λ_HU in the arterial and venous phases of adenocarcinoma and squamous cell carcinoma was performed. Results: (1) There was no significant difference in WC between arterial phase and venous phase in the two groups of patients. (P>0.05); (2) Compared IC, Eff-Z, and λ_HU in arterial phase and venous phase between the two groups of patients were statistically significant (P<0.05), IC and Eff-Z in arterial phase and venous phase in adenocarcinoma patients. λ_HU were higher than squamous cell carcinoma patients. The venous phase IC, Eff-Z, and λ_HU had higher diagnostic efficacy. Eff-Z had the best diagnostic performance at the venous phase. The AUC was 0.97. With 8.72 as the threshold, the differential sensitivity was 88.90% and the specificity was 94.70%. Conclusion: Quantitative analysis of multi-parameters of energy spectrum CT has certain diagnostic value for differentiation of esophagogastric junction cancer.