A multi-functional child high chair includes a pair of incurved fore legs and a pair of incurved rear legs collapsibly connected by a pair of circular joints, a first stretcher connected the lower end of the fore legs including a pair of casters at two end, a second stretcher connected the lower end of the rear legs including two caster at each end, a pair of rotary positioning joint slidably sleeved on the upper portion of the fore legs respectively and axially connected to a chair seat therebetween. The chair seat has an angle of elevation adjustable chair back, a large and a small platform and an adjustable foot rest. The rotary positioning joints facilitate the ascent and descent of the chair seat along the guide groove of the fore legs. A pair of drag devices respectively disposed in the fore legs and controlled by the rotation of the circular joints. When the legs are collapsed and laid on the ground, the chair is swinging to and fro as a cradle and/or stably supported by a pair of spare supports to become a bed for a child.