A highchair includes a building block table, a booster stool and a feeding chair. The bottom of the booster stool is detachably connected to the top of the building block table. The bottom of the feeding chair is detachably connected to the top of the booster stool. Four sockets are provided on the top surface of the building block table. An elastic cover that is adapted to the socket covers the top of each socket. A plurality of vertical grooves are spaced apart on the inner periphery of each socket. The bottom surface of each socket is provided with a first spring receiving groove. A plurality of protruding blocks are spaced apart on the outer periphery of each cover. The protruding block is matched with a corresponding groove. The bottom surface of each cover is provided with a second spring receiving groove.