“Urban Hanok” were mainly built between 1930's to 1960's in an urbanized area. It is consist of “Chae” and “Madang” which belong to the residential buildings. Combining of them makes up a living space. The Chae has two distinctive features. One is “Maru(a wooden floor)” and the other is “Ondol(underfloor heating system)”. The former is good for bearing the hot weather in summers and the latter is to survive in the cold winters. The unit of Chae and Madang functioned as a versatile living space or an environmental conditioning space. L-shaped urban Hanok building is consist of two parts. One zone is the main building and the other is wing building. Anbang is connected the main building and the wing building. Buok(a kitchen with a fuel hole) is located next to the Anbang toward the wing building, while Daechung(the main wooden floored room) is next to the Anbang toward the main building.<br><br> The purpose of this study is to identify the characteristics in relationship between Chae and Madang corresponding to the extension and alteration of L-shaped urban Hanok, which is a standard urban Hanok shape in central Korea. Based on the actual condition of the extension and alteration, we examined the spatial modifications in Chae and Madang and evaluated the characteristics of life style corresponding to the connection between Chae and Madang.<br> The results are follows:<br> (1) About the changes in the usage of Chae and Madang due to extension and alteration: 1) The usage of Chae: The backside of a building was extended to increase a room space or acquire a storage space. In this process, the gate part, which connected rooms in a Chae and front garden, was altered. When a gate was removed and replaced with a wall, the backside of a building and exterior space is disconnected. When a gate was replaced with a window, the space only allowed minimum lighting and ventilation. The passage to Madang is maintained, keeping traditional path of circulation intact. 2) The usage of Madang: Life behavior at the Madang changed corresponding to the demands of residents. For example, retired residents enjoyed gardening. However, Madang was maintained as an empty space for a parking spot, which was a different usage compared to when they just moved in. Madang had been flexibly used as a space to support the daily life of residents. Reason of emptying the center of Madang had changed corresponding to the variations in life pattern.<br> (2) About the changes in the connection between Chae and Madang: As characteristics of connection between Chae and Madang and space usages corresponding to the extension and alteration, it could be pointed out that rooms of Chae became more exclusive than when they moved in. For example, gates from rooms of Chae to Madang were removed and only the gate connecting Daechung and Madang was maintained. Toenmaru, which was a half inside and half outside space, used to connect Chae and Madang, but it turned into a pathway and storage space. Therefore, it changed the traditional lifestyle, which allowed residents to change the connection between interior and exterior by opening and closing windows and doors corresponding to seasons.