A butt-joining and engaging structure that allows to a pair of columns to be connected. The butt-joining and engaging structure has a seat body with a first connecting portion and a through hole, a stop part extends from an inner wall of the through hole toward the center of the through hole, a connecting member has a pair of ends defining a plug-in portion and a second connecting portion, and a position limiting part protrudes from the abutment surface of the connecting member. The first connecting portion is adapted to be affixed to one of the pair of columns. The second connecting portion is adapted to be secured to an end of the other column.