The project is located on the third floor of a red brick residential building in Shougang Road, with an area of about 20 square meters. In this extremely precious small space, the bathroom appears to be very small and cramped, with only the kitchen and hallway, as well as a bedroom. 20 square meters, not only undertakes the hostess's daily life of three meals a day, but also needs to take into account the need for temporary rest when her son, who is studying abroad, comes home. Although the space is small, it is not only the sustenance of the family's feelings, but also the receptive device of their lives. However, in use, it is love and hate for this family, and many inconveniences in use have made this old house gradually "criticized" by the family. How to rebuild the family's spiritual residence and how to meet all the living needs in a small space is a major challenge for our renovation.The narrowness of the space often makes people feel depressed, crowded and uncomfortable, which visually compresses the "sense of mass" of the space. So in this transformation, the first thing we need to do is to make the indoor line of sight transparent. However, due to the structural limitations of this old small house, the indoor partition structure can hardly be changed. Under this premise, we adjust the layout and comb the streamline to make the space appear more transparent. Let the "small" house look at the "small" but "complete with five internal organs", "transparent line of sight", "folding furniture", "storage" and other key words have become the main points of the design.Inside the space, the entrance of the bedroom is not only a central location of the whole house, but also a central point of traffic, which can lead to other functional areas of the home, so we first made a new layout here. The doors of the living room, kitchen and bathroom all use folding doors and sliding doors, and choose glass as far as possible in the material, so as not to affect the privacy of the space while reducing the sense of isolation and embarrassment of each functional space. The original closed space has been changed into an open or semi-open space, which will make the indoor line of sight transparent and create a sense of experience of the "big" space.