The invention discloses a process for forming welding of a large thick-wall sulphur-resisting tower barrel. A warming coiling forming scheme is adopted, and a steel plate is heated to 600-620 DEG C to undergo coiling forming. By controlling welding material impurity content and adopting a series of technological measures such as preheating before welding, welding sequence adjustment, dehydrogenation treatment after welding or stress relief treatment after welding, product weld joints meet various mechanical property and HIC (hydrogen induced crack) resistance and SSC performance requirements. The process has the advantages that heating time can be shortened; operation is simple; the steel plate thinning amount and elongation amount can be reduced; oxide skin is less; the steel plate can have high plasticity; the possibility of plate rolling machine overload can be reduced; the danger of brittle failure can be reduced; the groove angle is small; double wire welding is adopted, and the speed is quick; due to the fact that the groove angle is small, welding stress can be reduced, and anti-cracking capability of a welding joint can be improved; the automation degree is high, and welders perform operation conveniently.