In order to develop the design method of automatic orientation of eggs according to the pointed end and the blunt end, the mechanism of turnover motion of eggs on the convey rollers was analyzed and verified under the conditions of different verities of eggs and different diameter, center distance of convey rollers. Results show that the turnover motion of eggs on convey rollers was accordance with the principle of the cam. The transmission model of the egg, convey rollers and guide rod was built; and theoretical calculation method of the rolling distance of egg and the action distance of guide rod were developed. The design and calculation methods of the processing aisle width and bending length of guide rod were also proposed. The results of theoretical calculation were consistent with the test results. The rolling distance of egg and the action distance of guide rod had a positive liner correlation with the center distance of convey rollers and had a positive liner correlation with the diameter of convey rollers. The determination coefficients were all above 0.94. It is feasible and correct to use principle of the cam to analysis the mechanism of turnover motion of eggs on convey rollers.