The Palaces of Chosen dynasty in Seoul had lost its original features. The external appearance of the buildings that remains in palace nowadays, have got former conditions, but its enteriors are reconstructed or removed So we have a little knowledge of interiors of palace buildings, expecially of the door and window system. To clear up ambiguity of what kinds of door are selected, and sorts of using methods are prevailed, we must persuit from the latest building to the older building, and compare with documents. For that purpose the Chukchodang of Toksu palace is selected, which reconstructed in 1904, and compared with the document published in 1906. The consequence of investigation is that the palace buildings were adopted double or triple window system, and the main room have buffer zones, such as corridors or small rooms. And the main rooms were facing with wall paper, so metal fittings are hidden and wooden surfaces are hardly expose for the purpose of amenity.