The present disclosure provides a display mounting device, including a wall panel, an expansion hinge connection rod assembly, an adapter bracket, and a display bracket. The wall panel includes a main frame, two upper extension rods, and two lower extension rods. The main frame includes an upper beam, a lower beam, and a bearing plate. The two upper extension rods are respectively rotatably coupled to two ends of the upper beam to allow the two upper extension rods to be unfolded or folded relative to the upper beam. The lower extension rods are respectively rotatably coupled to two ends of the lower beam to allow the two lower extension rods to be unfolded or folded relative to the lower beam. Upper extension rods and lower extension rods can be folded and unfolded relative to the upper beam and the lower beam, thus meeting requirements of packaging size and installation size.