The invention discloses a truss-type steel diaphragm plate of a corrugated steel web cable-stay bridge. An upper steel beam of the truss-type steel diaphragm plate is connected with concrete in the upper portion a top plate of a box beam through a shear stud. The two ends of the upper steel beam of the truss-type steel diaphragm plate are hinged to a steel anchor box in a cable anchor area. The bottom of a lower steel beam is connected with concrete in the lower portion of a bottom plate of the box beam through a shear stud. Corrugated steel webs are arranged between the upper steel beam and the lower steel beam. A box chamber structure is formed by enclosing the corrugated steel webs, the upper steel beam and the lower steel beam. The two ends of inclined webs and a vertical web are welded to the upper steel beam and the lower steel beam respectively. One sides of the inclined webs and the vertical web are connected with the corrugated steel webs in a welding mode. Due to the fact that inclined webs and a vertical rod are welded to gusset plates, the truss-type structure is formed by the inclined webs and the vertical rod. The truss-type steel diaphragm plate is arranged on a stayed-cable of the steel web cable-stay bridge and the main beam anchoring area, the horizontal connection of the corrugated steel web cable-stay bridge is enhanced, the torsional stiffness of a main beam is enhanced, the horizontal whole performance is effectively improved, the construction is convenient, the quality is guaranteed, and the bridge service life is prolonged.