Reverse construction method reinforced concrete structure column connecting structure and construction method thereof

The invention relates to a reverse construction method reinforced concrete structure column connecting structure and a construction method thereof, the reverse construction method reinforced concrete structure column connecting structure comprises a pre-construction structure, a post-construction structure and a secondary pouring structure which are constructed in a soil layer, and the pre-construction structure comprises a concrete cushion layer, an underground structure top plate, a pre-stage underground structure column cap, a pre-stage underground structure upper section column, a frustum-shaped cavity structure and a grouting steel pipe; the bottom of the grouting steel pipe is communicated with the frustum-shaped cavity structure to form a secondary grouting channel; the post-construction structure comprises an underground structure column bearing platform, a temporary steel pipe support, a later-stage underground structure lower section column and a prismatic table-shaped structure, and the secondary p