Superconducting magnets of EAST(Experimental advanced superconducting tokamak)’s poloidal field have usually worked in zero load and variable load. It is economical that the current leads are designed as an overload lead. Some important parameters of poloidal field

such as heat load and temperature distribution

are calculated for current leads made of deferent materials at rated current and overload current in this paper. The principle of selecting material for manufacturing current lead is given. At the same time

the condition that the current lead can work at overload current is discussed.