Abstract: For CT imaging of a complex structural part, the equivalent thicknesses of different projection angles have large differences. So matched voltages are different for different projection angles. Variable voltage scanning is essential in the CT imaging of complex structural parts. A method for predicting scanning voltages at different angles was proposed for variable voltage CT imaging. The negative exponential function was used to describe the change of the equivalent attenuation coefficient with the imaging voltage. It is substituted into the function relationship of X-ray transmission rates of different voltages represented by equivalent attenuation coefficients. The empirical function relationship of different voltages with corresponding X-ray transmission rates was derived. The parameters were constantly updated for the function relationship with projection angle change in scanning voltage prediction. In the experiment of aluminum wedge block, compared with a method of literature, the max relative error of predicted voltage with the proposed method for all test points was decreased from 6. 24% to 3. 91%. The experiment of variable voltage CT imaging of aluminum phantom showed the effectiveness of the proposed method for scanning voltage prediction. From the experiments, the proposed method for scanning voltage prediction is suitable for the scanning voltage prediction of different angles in variable voltage CT imaging.