The metropolis' formation and development has its own rules. According to neo - classical economics, metropolis is an outcome that takes shape on the basis of city formation through division of labor and efficient hierarchical organizations. In the metropolitan development, how to decrease the transaction cost in cities so as to strengthen division of labor among cities, and how to improve the status of a central city of metropolis in the global division of labor, are very important. There are three metropolises in our country, namely, Hongkong, Shanghai, and Beijing. Each of them has different characteristics, advantages and disadvantages. The Hongkong metropolitan economic ring has the longest history, but has to upgrade its industries. Shanghai is developing very fast, but the function of central city must be set up. Cities in Beijing metropohs have littel economic connection but a good chance to develop owing to the 2008 Olympic Games. Each metropolis should make best use of its strong points and avoid its weak points, decrease its transaction cost, and heighten its economic capabilities.