Aiming at the crushing，sorting and recycling of the wasted printed wire boards，a threeroller shearing machine was designed which made use of the interlocking between the first and the second roll to extrude the printed wire board into strips after being cut by the edges of the cutter heads on the two rolls.〖KG-*4〗The strip extruded materials were broken in turn by the spiral teeth on the outer circumferences of the third roller at the edge of the guide plates，and small squares of materials were obtained.〖KG-*4〗The detailed structure of the threeroller shearing machine was designed，the working principle of the shearing process was analyzed,and the practical application of the shearing machine was introduced.〖KG-*4〗The application shows that the machine has the advantages of simple structure，low power consumption，low noise，high efficiency，simple operation and convenient maintenance.〖KG-*4〗It can cut the scrap printed wire board with good toughness，high hardness and high rigidity into small pieces，which lays foundation for subsequent fine crushing and material separation.