Abstract: With the development of the city,many old plants which are superior in location had stepped down from the stage of city. The old plants would be transformed into those having other functions. It was studied the skin renewal of old plants. The new buildings had different requirements in respect of function,technology and culture.Hence the skin renewal of old plants was divided into 4 modes: retention,fusion,coverage and reset of the skin. It was explored different types of architecture and their different design techniques adapting to different modes,hoping that the study could provide design reference for reforming old plants.