The problems of energy density diagnosis of compression plasma flows are introduced in this paper. Based on the energy dissipation analysis and the heat conduction calculation model, aiming at the errors caused by vaporization, an energy density correction method based on measured mass loss is proposed, and the input energies required to lose the same mass are deduced through the finite element calculation of surface receding. The energy density correction is evaluated, and the corrected energy density obtained by this method is in good agreement with the experimental results. However, to obtain more accurate energy density, it is necessary to correct the energy density for shielded plasma and recoil stress wave or develop a more accurate energy density diagnosis method.