The present invention discloses a lifting desktop with a compact structure, comprising a desktop platform, a base frame below the desktop platform, and two sets of support frame assemblies, assistance assemblies and locking assemblies which are symmetrically arranged on two sides between the base frame and the desktop platform, wherein the base frame comprises lower side-plates, and the desktop platform comprises upper side-plates; each of the support frame assemblies comprises two support legs which are pivoted to each other in scissors by a central pivot and spanned on two sides of the respective lower side-plate; each of the support legs has a fixed pivot end pivoted to the respective lower side-plate or upper side-plate and a free end movably connected to the opposite upper side-plate or lower side-plate on the same side.