The effects of egg kinds and working parameters on the mechanical automatic orientation motions of eggs were studied by using self-made test device. The results showed that, there were differences among the axial and the turnover motions of cottage eggs, farm eggs and duck eggs. There was no obvious effect of longer and shorter axes of eggs on axial motion. The time for eggs to turn to the critical condition increased as the longer axis increased. There were obvious effects of working parameters on the axial and the turnover motions. Considering the speed and the stability of the two motions, the best ranges of the working parameters for mechanical automatic orientation device of eggs were obtained: diameter of convey rollers was about 40 mm, center distance of convey rollers was 55-65 mm, convey speed and peripheral speed of convey rollers was 54-78 mm/s, the bending angle of guide rod was 20-30 degrees and the distance between guide rod and convey rollers was below 5 mm. (C) 2014 Elsevier Ltd. All rights reserved.