Objective:To observe the feasibility and value of one-step spectral imaging and perfusion imaging in diagnosis of solitary pulmonary nodule. Materials and Methods : 47 patients with SPN proved by pathology underwent perfusion scan with using gemstone Spectral imaging mode,who were divided into malignant group(28 cases),benign group(19 cases).The parameters of CT perfusion including BV,BF,MTT,PS were analyzed .IC,NIC and slope rate of spectral curve of both arterial and venous phase were measured and calculated.The independent sample t test was performed to compare quantitative parameters between malignant and benign SPN.Different parameters ROC curves were taken to give the diagnostic efficiency and the diagnostic sensitivity and specificity. Results :BF、BV、PS in malignant SPN were highter than benign SPN.IC、NIC and slope rate of spectral curve in malignant SPN in both phases were highter than benign SPN .The area under curve(AUC) of BV、PS and venous phase NIC were larger,and they were respectively 0.712、0.718、0.934.When BV>6.16ml/100g、PS >19.13ml/(min·100g)、NIC(venous phase)>0.18,the sensitivity and the specificity of diagnosing malignant and benign SPN were resspectively 78.6%、73.7%,75.0%、72.2%, 92.9%、80.5%.Combined the parameters of BV and venous phase NIC,the sensitivity and the specificity of diagnosing malignant and benign SPN were 100%、84.2%. Conclusions :One-step spectral imaging and perfusion imaging can accept more parameters and both of them are helpful to diagnosis of SPN,combining perfusion imaging and spectral imaging can receive high sensitivity and specificity.