Abstract: In order to illustrate the mechanism of axial motion of eggs on the delivery supporting rollers, the principles of dynamics and geometry were employed, and obliquity variations of the major axis of eggs on a plane and two parallel rollers with equivalent diameter, as well as the impact of different diameter and center distance on the obliquity were studied theoretically and experimentally. It was revealed that there exists a sole balance-contact-circle to which an egg was analogously as the balance of the homogenous egg-shaped body was put on a plane or two parallel consistent supporting rollers. The obliquity calculation method of balance-contact-circle under different support conditions and the relations between the obliquity and the support pattern as well as the construction parameters were established. It was found that the obliquity of homogeneous egg-shaped body or eggs balanced on plane was smaller than that on two parallel supporting rollers. Concerning the latter, the obliquity was negatively correlated with the diameter (25-50 mm) of supporting rollers, and positively correlated with the center distance (47-67 mm). With support conditions constant, obliquity was dependent on the basic characteristic parameters such as the size of eggs, major axial diameter, minor axial diameter, mass and the volume. The experimental results show that the application of balance-contact-circle in the analyses of obliquities under different support conditions is accurate and feasible, which can provide a basis for analyzing the axial motion of eggs on the delivery supporting rollers.