Abstract：This paper proposes an interdisciplinary approach to the organic regeneration of old neighborhoods based on the “gravity of the commons”, and a practical approach to community regeneration based on public space creation. The “gravitational force” of public space exists between space and people, directly proportional to the public space quality and people’s demand for public space while inversely proportional to the cost of distance due to accessibility of space. Based on the theoretical framework of “public gravity”, the study proposes a specific planning concept for the regeneration of the old district of Nanjing’s Xinjiekou Huaihai Road area. Our design proposal addresses the current predicament of the public space shortage, the blockage of community vitality and disappearing cultural characteristics. We specify four measures including identifying potential public space, constructing community public system, simulating public nodes, and creating a sharing and co-governance mechanism. Such measures collectively stimulate community vitality, promote service upgrade, and urban regeneration through shared urban spaces and diversified activities.