[en] For cooling water transition joints used in EAST divertor heat-sink in the process of plasma disruption its main electromagnetic load was analyzed and calculated, a new transition joint structure were put forward. Through finite element analysis of the new structure under the extreme load, pre-research and test of welding, the joint structure and the fabrication scheme were optimized, finally the cooling water transition joints design used in divertor heat-sink was accomplished, and successfully applied to the upgrade of EAST divertor heat-sink. (authors)