Abstract: The technique using thermal tensioning and trailing intense cooling simultaneously to reduce welding distortion was investigated by both numerical simulation and experiments.Numerical simulation shows that trailing intense cooling tends to cause obvious longitudinal plastic tensioning in the weld, while thermal tensioning can create plastie tension in the adjacent zones to the weld.When they are coupled to use the longitudinal plastic compressive strain in the weld and its adjacent zones can be reduced markedly by thermal tensioning in the heating stage and the plastic tensioning following in the cooling stage will be increased by trailing intense cooling .The former takes place more remarkably in the zone adjacent to the weld while the latter in the weld, so the compressive strain will be evenly cancelled out further and the residual distortion of welded piece will be reduced greatly .The same conclusions were drawn from aluminum alloy welding experiments.