Abstract: Spectral imaging is a new technique in the field of CT imaging in recent years, with many parameters, quantitative analysis of imaging characteristics, the main technology including material separation, single energy image, can measure the spectrum curve and the effective atomic number.Through the comprehensive application of various parameters and analysis tools, spectrum imaging can reflect the characteristics of lesions, and has potential value to determine the source and scope, differential diagnosis etc..The screening of lung cancer, the identifying of benign and malignant pulmonary nodules and other aspects of the study also achieved initial results.This article focuses on the spectrum technology and its application in diagnosis of lung cancer.