A height-adjustable folding desk includes a desktop and a leg-support connected to the lower surface of the desk. The leg support includes a first “” shaped rod and a second “” shaped rod. The two supporting-foot of the first “” shaped rod are rotationally cross-connected with the two corresponding supporting feet of the second “” shaped rod respectively. The horizontal rod of the first “” shaped rod is pivotally connected with an end of the lower surface of the desktop, and the other end of the lower surface of the desktop is fixed with an adjustable equipment, the lower surface of the adjustable equipment comprises grooves which may contain the horizontal rod of the second “” shape rod. The height of the folding table can be achieved by adjusting the position of the horizontal rod of the second “” shaped rod.