The invention discloses a glass curtain wall keel structure and an installation method thereof. The structure comprises vertical columns and a beam, wherein each vertical column comprises two movablecolumns and a fixed column, each fixed column comprises a fixed vertical frame, and the upper end of each fixed vertical frame is provided with an insertion core; each movable column comprises a movable vertical frame which has a cross section same with the corresponding fixed vertical frame, and each insertion core is a closed profile of which the size is less than that of the corresponding fixedcolumn. The installation method comprises the steps that first connecting parts is arranged on the movable columns through second connecting parts; and the first movable column is in clamped connection with the corresponding fixed column through the corresponding insertion core. The glass curtain wall keel structure and the installation method thereof have the advantages that the problems in theprior art that complex mounting joints and inconvenient disassembly and replacement of a closed beam can be solved, the structure is simple, and the glass curtain wall keel structure is safe and firm.