A transition device was developed to solve the low efficiency,high breakage rate and low space utilization of domestic egg weight classification machine. It can transform the egg transport form from six row to single row and turn the eggs over with turning the long axis from horizontal to vertical to pack more quickly. Based on the three-dimensional model built,the kinematics of dynamic part and operative part were analyzed. The dynamic part is made up of a inscribed double eccentric sprocket structure. The solving equations of master-slave sprocket were listed between angular displacement and drive ratio,and the precise relationship of matching position between the operative and the power part was found out.