The effect of severe plastic deformation on the properties and microstructure of W-Cu composites produced by multi pass hot extrusion with steel cup was investigated.W-Cu composites were sintered at 1100℃and then the sintered billets were hot extruded at 900℃ with different extrusion ratios.The second hot extrusion was performed at 900℃.The plastic deformation of copper phase plays a dominant part during the whole extrusion processing.The microstructure evolution of W phase and Cu copper phase during the processing of severe plastic deformation can be divided into three stages.Experimental results and modeling indicate that the W agglomeration will be broken into fine particles effectively distributed homogeneously in the elongated Cu phase during the third stage when the accumulated plastic deformation amount achieve 97.6% after the second extrusion.