Abstract: The moving transition equation of drawing theory is introduced.It is pointed out that the assumption of density field on ellipsoid drawing theory violates the fundamental premise of the continuous medium hypothesis.The defects of moving transition equation of ellipsoid drawing theory based on existing density field assumption are demonstrated.Also，a new moving transition equation is constructed to further improve the foundation of ellipsoid drawing theory.

Key words: Ellipsoid, Drawing theory, Density field, Moving transition equation