The invention discloses an external-expansion type medical suturing nail with a nail body falloff promoting plate. The suturing nail comprises rod-shaped nail angles and a nail beam, wherein the cross sections of both the rod-shaped nail angles and the nail beam are of rectangular structures; an n-shaped structure is formed by the two rod-shaped nail angles and the one nail beam, and corners where the rod-shaped nail angles and the nail beam are connected are of arc-shaped structures; the nail body falloff promoting plate is arranged on the nail beam; the side face of the nail body falloff promoting plate is butted with the upper side face or the lower side face of the nail beam; and the front plate surface of the nail body falloff promoting plate is horizontal with the front side face of the nail beam and the rear plate surface of the nail body falloff promoting plate is horizontal with the rear side face of the nail beam. The suturing nail disclosed by the invention, by virtue of the nail body falloff promoting plate, is conducive to the falloff the a nail body; the two rod-shaped nail angles, which are in the form of external expansion, are capable of preventing the nail angles from bending inwards in the process of piercing into skin; and corners on the outer sides of the ends of the two rod-shaped nail angles are cut off, so that the outer sides of the ends of the rod-shaped nail angles are formed as inclined planes, and the two external-expansion rod-shaped nail angles bend inwards when the rod-shaped nail angles are in contact with a nail anvil, so that the success rate of a suturing operation is greatly improved.