By means of the rapid heating followed by water quenching, thermal shock experiments were conducted for CuW70 alloys to study the variations of mechanical behaviour. On the other hand, the simulation with finite element method was implemented to analyze the variations and the distributions of the temperature and the thermal stresses of CuW70 specimens during thermal shock process. The results show that the strength of CuW70 alloys degenerates and the ductility is improved after repeated thermal shock, and the maximum thermal stress appears at the beginning of heating and quenching period. The alternated thermal stresses which vary between tensile and compression stress will be applied on the internal and the external of CuW70 alloys during repeated thermal shock.