A mandrel screw-on machine pre-screwing and auxiliary machine device comprises a PLC control system and further comprises a rotating pre-screwing mechanism, a double-carrier-roller mechanism, pull rod driving mechanisms and supporting carrier roller mechanisms, wherein the rotating pre-screwing mechanism and the double-carrier-roller mechanism form a pre-screwing mechanism assembly, inlet and outlet mechanism assemblies which are respectively composed of each pull rod driving mechanism and a plurality of sets of the supporting carrier roller mechanism are arranged at the two ends of the pre-screwing mechanism assembly respectively, the pull rod driving mechanisms are connected with the plurality of sets of supporting carrier roller mechanisms through pull rods, and the rotating pre-screwing mechanism, the double-carrier-roller mechanism, the pull rod driving mechanisms and the supporting carrier roller mechanisms are all connected with the PLC control system. The mandrel screw-on machine pre-screwing and auxiliary machine device solves the problem that imported equipment is relied at present, fills in gaps in mandrel screw-on equipment localization, and particularly solves the technical problem that a mandrel with a phi 460mm large diameter can not be screwed in a standard mode.