Abstract: Objective: To investigate the value of energy spectrum CT multi-parameter quantitative analysis in the differential diagnosis of lung squamous cell carcinoma and adenocarcinoma. Methods: Seventy-five patients with lung cancer who were confirmed by pathology and underwent energy spectrum CT scanning were collected, including 40 cases of squamous cell carcinoma and 35 cases of adenocarcinoma. We measured and compared the energy spectrum parameters of arterial phase and venous phase between the two groups. Results: The spectrum curve of adenocarcinoma (λ_{40～65 keV}) in arterial and venous phase, effective atomic number, concentration of iodine (water) and standardized iodine concentration were greater than that of squamous carcinoma, the difference was statistically significant, the difference of water (iodine) concentration between the two groups of arterial phase held no statistical significance, the water (iodine) concentration of adenocarcinoma was lower than that of squamous cell carcinomas, the difference was statistically significant. The results of ROC curve analysis showed that the energy spectrum (λ_{40～65 keV}) in the venous phase was of great value in the differentiation of squamous cell carcinoma and adenocarcinoma, with the AUC of 0.839, the sensitivity of 88.6% and the specificity of 72.5%. Conclusion: Adenocarcinoma and squamous cell carcinoma of lung show different energy spectrum CT parameters. It holds certain value to distinguish them, which can provide a new method for preoperative diagnosis.