The invention discloses a corner brace used for an aluminum-wood door/window. The corner brace used for the aluminum-wood door/window comprises a corner brace body. The cross section of the corner brace body is in a right angle shape, screw mounting holes are machined in both sides of the end surface of the corner brace body and the end surface of the right angle, and a positioning groove used in cooperation is machined in the inner side wall of the right-angle portion of the corner brace body; and a technology groove is machined in the right-angle portion of the corner brace body, and the two ends of the corner brace body are machined to be of a chamfer structure. By adoption of the corner brace for the aluminum-wood door/window, connection on the right-angle portion of the aluminum-wood profile door/window is made to reach the flatness with the standard angle, the corner brace is convenient to mount and adjust, the connection strength of the aluminum-wood profile body is improved, the service life of the aluminum-wood profile body is prolonged, and actual use requirements are met.