Abstract: The present disclosure provides a desktop assembly and height adjustment frame mechanism that facilitates height adjustment of a desktop. The desktop assembly and height frame adjustment mechanism includes a desktop assembly having upper and lower platform surfaces; and a frame adjustment mechanism for adjustably supporting the desktop assembly. The frame adjustment mechanism further includes: an upper support frame, including a left upper bracket and a right upper bracket; a base support frame, including a left lower bracket and a right lower bracket; an X-shaped support frame that pivotally connects the upper support frame and the base support frame, wherein the X-shaped support frame further includes a pair of left and right first pivot legs pivotally interconnected at the center to a pair of left and right second pivot legs; a pair of hydraulic cylinders which facilitate raising and lowering the upper and lower platform surfaces; and a pair of locking levers pivotally attached to the upper platform.