Abstract: The rotary mechanism is an important ergonomic part of the integrated spot welding gun. It is directly related to the operation of welding gun which is the main hand-held spot welding equipment for automobiles. Different structures of rotary mechanism were researched,which includes deep groove ball bearing,ball bearing structure without inner and outer rings,four point contact ball bearing with constant cross section and wire race ball bearing. A preferred rotary mechanism with bearing was proposed by comparing the characteristics and applicability of various bearings.