The invention discloses an armrest synchronous lifting link mechanism which comprises a backrest, a seat frame, an armrest, a rotating shaft and a link device, wherein the link device comprises a rotating part, a fixed part and a connecting part; the fixed part is fixedly arranged on the seat frame; the rotating shaft sleeves the backrest; one end of the rotating part sleeves the rotating shaft and the other end is arranged on the fixed part; the backrest is connected to the seat frame by virtue of the rotating part; the armrest sleeves the rotating shaft; and one end of the connecting part is connected to the armrest and the other end is connected to the fixed part. According to the armrest synchronous lifting link mechanism disclosed by the invention, the armrest lifts when the backrest is rotated, and under the action of the link device, the armrest is constantly parallel with the seat frame; so that, the link mechanism is convenient in using.