The invention relates to the technical field of automobile rotating shaft welding, in particular to an automobile rotating shaft welding forming surface fine treatment system. The automobile rotatingshaft welding forming surface fine treatment system comprises an automobile transmission shaft and further comprises a clamping device used for clamping the automobile transmission shaft, an autorotation device used for rotating the clamping device and a cutting and grinding device used for removing welding slag. The clamping device comprises supporting columns, a mounting table, a clamping groove, a clamping block, a containing groove, a clamping column, clamping torsional springs, clamping plates, stirring strips and an inner supporting mechanism. The autorotation device comprises a supporting frame, a driving groove, autorotation gears, rotating columns, a rack groove, a matching rack, a rotating motor and a driving gear. The cutting and grinding device comprises a combined groove, a rotating table, a mounting column, a telescopic air cylinder, a matching block, driving teeth, a mounting disc, a mounting block and an executing assembly. The automobile rotating shaft welding formingsurface fine treatment system has the effects of multiple functions, automatic polishing and reduction of potential safety hazards to workers.