Abstract: Based on the loose body mass balance equation and density empirical formula obtained from the ore-drawing tests， it was proved that the density equation presented in the foundation of the quasi-ellipsoid drawing theory satisfied the reality as well as the theoretical requirements. The theoretical expressions of the actual vertical velocity and velocity viscosity coefficient were established， and the velocity viscosity coefficients and the actual granular velocity equation were obtained according to the density equation and mass balance equation of the moving body， which are exactly the same as the one when the quasi-ellipsoid drawing theory was founded. The actual granular velocity equals the product of the ideal granular velocity and velocity retardation coefficient. The research results show that the density equation， the actual granular velocity equation and the velocity retardation coefficient formula have sufficient theoretical basis when the quasi-ellipsoid drawing theory was found.

Key words: Quasi-ellipsoid, Drawing theory, Density equation, Velocity equation, Velocity retardation coefficient