Abstract: A completely foldable multi-function highchair is provided with the functions of adjusting the position of the tray, the height of the seat and the inclination of the seat. The multi-function highchair comprises: front legs and rear legs, connected to the folding mechanisms with folding and expanding functions; a height-adjusting mount, provided on the front legs for adjusting the height of the seat; a back of the seat, provided with seat inclination adjusting device for adjusting the inclination of the seat; armrests, pivotally connected to the back and adapted to be rotated upwards during the folding operation; a seat support, pivotally connected to the back and adapted to be rotated upwards to the upright position during the folding operation; and a footrest, pivotally connected to the seat support and adapted to be rotated upwards during the folding operation.