From 202 1, China changed from shed to old. The so-called "old renovation" refers to the renovation of old residential areas with a room age of more than 20 years on the basis of less demolition and large construction, which mainly includes the renovation of internal and external walls, the reinforcement of stair corridors, the painting of walls, the replacement of old pipes, the installation of elevators, and the increase of residential greening, parking spaces and fitness venues. The purpose is to improve the living environment and quality of life of residents in old residential areas.