Macao is a population-dense consumes society which is lacking in nature resources and almost all of her life support goods and raw materials depend on import. In the recent years, Macao has experienced an economic boom, as well as social development. How can Macao survive herself against these shortcomings? This paper attempts to incorporate emergy flow analysis to investigate the urban development sustainability of Macao’s environment and economy in 2003. The research has revealed that the total used emergy was 220×1020 sej (Solar emjoules)，and the imported emergy of Macao was 216×10²⁰ sej, while the exported emergy was about 147×10²⁰ sej in 2003. The gambling and tourism industries (refer to tourism) are the main profit earning industry of Macao, and they have captured D|S 5.21 billion in 2003, with the emdollars emergy 86.5×10²⁰ sej, while at the same time tourists only consumed 32.6×10²⁰ sej, the emergy surplus of tourism was 53.9×10²⁰ sej, the contribution impact ratio of tourism was 2.65 times. Macao also benefit from the exchange with Mainland China since they have different Emergy/D|S ratio when using the same currency to compare, the emergy exchange ratio was 1.8 times. These two kinds of emergy surpluses are the most important sources for sustainable development of the Macao urban ecosystem. Finally the sustainability of Macao has been discussed.