The invention relates to an illuminating system with an all-purpose lamp bracket and a curtain wall and a construction method thereof. The illuminating system with the curtain wall comprises the lamp bracket and a lamp, wherein the lamp support comprises a guide rail, a rotating shaft, a support arm which is indirectly connected to the rotating shaft and a lamp holder which is connected with the support arm; the guide rail is positioned between the curtain wall and a main body structure, is fixedly connected with a curtain wall keel by a stable support piece and is fixedly connected with the main body structure by a reinforced support piece; the rotating shaft is positioned in a guide groove of the guide rail; the lamp is fixedly connected with the lamp holder. The construction method is simple and convenient; each member is precast according to the actual situation; the curtain wall keel, the reinforced support piece, the stable support piece, the guide rail and the curtain wall are arranged sequentially, the rotating shaft is pushed along the guide groove from bottom to top, and after the rotating shaft is arranged completely, the support arm corresponds to sliding chutes; the lamp is fixed, a handle is rotated to make the support arm rotate at 90 degrees along the sliding chutes, the lamp rotates at 90 degrees with the support arm to directly face the curtain wall, and the installation and fixing of the integral illuminating system are completed. The illuminating system and the construction method are widely used for the curtain wall illuminating system.