The thermal deformation behavior of W80-Cu20 composites was investigated by hot compression with Gleeble-1500 thermal simulation system in the temperature range of 810-970℃ and strain rate range of 0.01~ 10s_^-1 up to a true strain of 0.69. Based on modi?ed dynamic materials model (MDMM) and Malas"s criterion, the power dissipation map and processing map were established. Combined with microstructure, the reasonable parameters of hot processing were determined. And the damage formation of W80-Cu20 composite was analyzed. The results show that the stress-strain curves of W80-Cu20 composite are typical dynamic recrystallization (DRX) type curves, and the peak stress increases with the decreasing of deformation temperature and the increasing of strain rate. The preferable processing zones of W80-Cu20 composite were determined as follows: 840-885 ℃, 0.2-1.42 s_^-1 and 885-917℃, 0.83-2.05 s_^-1. The damage modes of W80-Cu20 composites involve Cu phase rupture, W-Cu interfacial separation, W-W grain boundary separation and W-grain crack.