A small low speed milling machine has been designed for household use. The device adopts vertical roller mill grinding, and is equipped with the outer cylinder rotation drive screw lift to achieve a uniform grinding mechanism which ensures the produced flour's nutrition structure intact. The function structure and working principle of the mill, the kinematics theory of the roller mill and the lifting mechanism are applied. A new structure of the whole machine as well as its key parts has been performed. The software EDEM has been used to carry out the simulation of the particle transport of flour, and the factors which affecting the efficiency of material conveying have been studied. Thus this study provides reference for the selection of the motor and the design of the whole machine.