The invention discloses a file binding device for engineering audit. The device comprises a base; a cavity is formed in the base; a vertical plate is fixedly mounted on one side of the top surface ofthe base; the top surface of the vertical plate is hinged with a horizontal pressing plate; a mounting plate is fixedly mounted on the bottom surface of the pressing plate; the bottom surface of the mounting plate is hinged with two support rods; the two support rods are distributed front and back; a horizontal support plate is arranged under the mounting plate; two first chutes with dovetail sections are formed in the top surface of the support plate; and the two first chutes are distributed front and back. When staples are used for binding files, first fixing pins, second fixing pins, thirdfixing pins and fourth fixing pins can be upwards bent in different directions to reach a horizontal state, so that the staples achieve tight grabbing in different directions, the grabbing force of the staples is improved, the file binding is firmer, the file scattering is prevented, and the use is convenient.