Abstract: A raised floor and an assembling method thereof includes a plurality of raised floor boards, wherein a plurality of raised floor boards are assembled and connected to form an integrated floor, an edge of the integrated floor close to the wall is supported by a leveling beam, and leveling screws are arranged below connecting positions of two adjacent raised floor boards, a reserved expansion joint is arranged between the edge of the integrated floor and the wall, and a position above the integrated floor close to the wall is fixedly connected with frame beam by an expansion screw. An edge of the raised floor board body structure is processed, so that the raised floor boards can be assembled through lap joint and connection of structures, and supported through the leveling screws when they are in mutually lap joint for assembly.