The invention discloses a curtain wall adjustable connection joint structure based on transformation angle iron and a construction method. The curtain wall adjustable connection joint structure comprises a fixed support and the transformation angle iron, the fixed support is fixed onto a curtain wall supporting structure, and the transformation angle iron is used for fixing a connecting hanging hook mounted on a curtain wall plate. The construction method includes the steps: firstly, pre-processing; secondly, fixed support and connecting hanging hook installation; thirdly, angle iron body installation; fourthly, curtain wall unit installation; fifthly, limiting part installation. The structure is reasonable in design, simple and convenient to construct and good in use effect, the fixed support fixed onto the curtain wall supporting structure and the connecting hanging hook mounted on the curtain wall plate are reliably connected, force transformation is achieved, and a fixed position of the fixed support on the curtain wall supporting structure, a mounting position of the transformation angle iron on the fixed support and a fixed position of the connecting hanging hook on the curtain wall plate can be simply, conveniently and flexibly adjusted in the mounting process, so that connecting requirements of different connecting joints of special-shaped curtain walls can be met.