With the continuous growth of urban rail transit operation scale of China, the importance of sustainable development of rail transit is increasingly prominent. As the only profitable Metro Company in the world, MTR"s business model is of great significance of China"s mainland rail companies. Through the analysis of the profits of various businesses, it is found that as MTR enters the operation Era, "Rail + property" is no longer the key factor of its sustainable development. Instead, it is the operation business such as Transport Operations and Station Commercial Business. The profit of these businesses is derived from the large amount of passenger flow within the MTR, which is known as "flow realization ". This shows that land resources can only support the construction of rail transit, and it is passenger flow that can support its development.