The regularization method for density reconstruction of axially symmetric objects using a single Xray projection is described. The regularization mathematical model is established according to a prior information of the reconstructed object. The numerical solution can be obtained by solving symmetric positive definite systems of linear equations. Numerical simulation examples illustrate the accuracy of the reconstructed density including edges and values. It has been testified that the regularization method is not sensitive to the measured data noise. This ensures that the small error of measured data will not cause strong oscillation of numerical solution.