Objective: To investigate the feasibility of quantitative analysis of calcium content using equation of spectral curve of CT spectral imaging. Methods: Solutions of calcium chloride of different concentrations were filled in multiple tubes. GE Discovery CT750 HD CT scanner was used for spectral imaging of these solutions. After spectral scan, ROI analysis was used to obtain generate spectral curve of different solutions. All curves were solved to form equation from keV to CT values. Then the relationship between the constants of equations and the concentrations were analyzed. Results: Analysis of the spectral curves from the solutions of calcium chloride resulted in the equations as: Y=a×exp(b×X)+c×exp(d×X), Y represented CT value, X represented keV. Further analysis revealed that b and d remained almost constant and showed no correlation with iodine concentration. Constant a and c had linear correlation with concentration. Conclusion: Analysis of spectral curve equation reveals the constants that representing the nature of calcium and the concentration, respectively, which will be helpful to the identification and quantification of calcium content. Copyright © 2013 by the Press of Chinese Journal of Medical Imaging Technology.