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Rapid modern urbanization in China is evidenced by a substantial development of densely populated medium to high-rise buildings during the past decades.To accelerate economical activities,centralized commercial areas surrounded by high-density residential units are being developed throughout the country.Behind the rapid increase in GDP,China is now seriously suffering from the deteriorated air quality and the thermal energy consumption problems.Although the Chinese Ministry of Construction has established a green building standard for a period of time,however,the sustainable development measures are still not commonly adopted by the building industry,even for some simple ideas,such as natural ventilation and thermal consumption controls.In view of this,this paper offers both a broadbrush overview of the natural ventilation and thermal building system,and a progressively more focused look at the energy consumption issues,from the citys urban cooling perspective.Acting as a typical model of urbanization in China,especially for Pearl River Delta region,the situation in Hong Kong is being studied and analyzed in this paper.The over congested tall building configuration around the coastal area created the "Wall Effect" and blocked the natural ventilation,trapped green house gases and suspended particles within the city.In addition,the relatively hot and humid climate has further led Hong Kong toward dependency on air-conditioning for thermal comfort and directly makes buildings consumed nearly 90 ％ of total electricity in Hong Kong.Hong Kong is a typical case,and the alarming fact is that natural ventilation and thermal consumption problem is developing into a global issue.However,the existing green building standards adopted in Hong Kong,based on its original codes developed by western counties,paid no particular attention on building configuration and thermal envelop strategy.This paper also moves on to offer some partial,but practical solution to the Hong Kong situation-that of saving energy through the implementation of low thermal energy transfer building envelopes and promoting natural ventilation via urban planning and concession policies.Simulation result demonstrated that with the current state of building technology,reducing radioactive thermal transfer is more cost effective than implementing other means of envelope insulation,besides,by providing special treatment to building design and increasing the spacing between tall buildings,thermal energy consumption can be significantly reduced.