Abstract: An adapter with improved connection function applicable to connection of KD furniture including cabinet, chest or rack, comprised with four 90-degree angular grooves, a cross clamping structure protruding from one side of the adapter, a hole in the center of the clamping structure, the clamping structure including two parallel clamping boards, multiple slip stoppers provided at equal spacing on the inner side of each clamping board, and an insertion structure provided externally to the clamping structure, a deeper hole provided to the insertion structure to connect to more parts, e.g. a door panel, cabinet, chest or a rack frame.