The research status of fusion welding of nickelbased superalloys and cobalt-based superalloys are reviewed.The mechanism of welding cracking and the effects of welding process and alloy compositions on weldability are described here. The weldability of nickel-based superalloys can be improved by adjusting alloy compositions,changing the morphology of precipitations and grain boundaries,and choosing reasonable welding process parameters. Compared with the precipitationstrengthened nickel-based superalloys,the solid-solution strengthening cobalt-based alloys have good weldability and exhibit superior welding fusion interface and high cracks resistance. In recent years,researchers have found that the lattice mismatch of γ and γ’ is positive in precipitation-strengthened cobalt-based superalloys,which would effectively reduce the sensitivity of welding strain aging cracks. The novel precipitation-strengthened cobalt-based superalloys have excellent mechanical properties and weldability,which are likely to become one of the most promising high-temperature materials.