To solve the general problem that copper staves experience water pipe failure in blast furnace，the effects of constraints on the thermal stress distribution of copper stave water pipe are investigated by thermal-structural coupling analysis.In this study，a mathematical model of thermal stress of copper stave is established to analyze the thermal deformation and stress distribution of water pipe under subject to different types of constraints.The results show that the thermal stress on the root of water pipe is larger than others as the terminal of water pipe is free or being fixed.But the equivalent stress on the root of water pipe is just 45 MPa as the terminal of water pipe is free，which is lower than the yield strength of pure copper.The equivalent stress on the root of water pipe is about 272 MPa as the terminal of water pipe is being fixed，and exceeds the yield strength of pure copper.The water pipes should be flexible.The maximum equivalent stress is about 600 MPa as the water pipe is subjected to the constraint of shell，which is far beyond the yield strength of pure copper.The maximum displacement is located at the end of water pipe and is about 1.73 mm.Then the diameter of the hole should be 120 mm with taking installation error into consideration.