The invention provides a quickly replaced type copper block heat dissipation device which comprises at least one heat dissipation assembly, wherein each heat dissipation assembly is provided with a plurality of copper block assemblies, each of which is provided with a heat dissipation copper block, and at least one connection device, each of which is detachably mounted on two adjacent copper block assemblies to connect the two adjacent copper block assemblies. The quickly replaced type copper block heat dissipation device is easy and convenient to operate, high in generality, good in cooling effect and quickly assembled and disassembled; via quick cooling of a weld, the heat input volume of a mother material is effectively reduced, generation of internal stress is reduced, and an existing welding process is improved.