This project seeks to examine the determinants of economic growth by using large-scale urban mobility networks. Leveraging the fine-grained phone trajectory data, the project constructs a microscopic mobility network to describe the connectivity between economic activities in the complex urban environment. The research found that the mobility networks are highly predictive for economic outcomes, such as income and property values, across the metropolitan areas in the US. Although researchers hypothesized that human dynamics can predict economic growth, this project is one of the first that corroborates this intuitive hypothesis with concrete empirical support.