Interior orientation autorotation impact initiating device for oil gas well completion

The invention relates to an interior orientation autorotation impact initiating device for oil gas well completion. A guide sleeve is a part of the upper end of the impact initiating device; an orientation key is fixed on the guide sleeve through welding; the lower end of the impact initiating device is connected with an orientation connecting pipe through threads; an detonator is arranged inside the lower end of the impact initiating device; then the orientation connecting pipe is connected with a connecting gun connector through a connecting pipe; a positioning disc is fixed inside the orientation connecting pipe, and keeps the same axial direction with the orientation connecting pipe and the orientation key on the guide sleeve in a positioning key way; the assembly components are positioned inside an outer tube and are righted and supported through bearings. The initiating device realizes the measurement in the gun perforation direction at the upper end of an initiating part of a perforating gun, and effectively improves the accuracy of interior orientation gun perforation. An orientation measurement method based on the initiating device solves the problem of difficulty in interior orientation gun perforation measurement.