The invention relates to a machine frame vertical plate structure of a small-scale single-rotor unmanned helicopter. The machine frame vertical plate structure comprises a vertical plate and a connecting block, wherein the vertical plate is in a bar shape; a plurality of technological holes are formed in the vertical plate; bottom plate connecting holes are formed in the lower end of the vertical plate; gearbox lower plate connecting holes are formed in the upper end of the vertical plate; an arc-shaped notch A is formed in the end part of the lower end of the vertical plate; an arc-shaped notch B is formed in one end of the connecting block; the connecting block is connected to the end part of the lower end of the vertical plate through a bolt; the arc-shaped notch B in the connecting block is opposite to the arc-shaped notch A formed in the end part of the lower end of the vertical plate to form a landing gear mounting hole. The machine frame vertical plate structure disclosed by the invention has the advantages that the structure is simple, the technological holes are formed in the vertical plate to reduce weight, the vertical plate is matched with the connecting block to form the landing gear mounting hole, the mounting positioning support of a landing gear is provided, a positioning slot A and a positioning slot B are respectively formed in the upper end and the lower end of the same end surface, and positioning is facilitated when the bottom plate and the upper plate of the gearbox are connected with the vertical plate.