Abstract: To build Chongqing to a national ecological garden city, the urban heat island evaluation and study were analyzed.The study reality of urban heat island and some problems encountered were analyzed too.Study scheme of urban heat island oriented to building a national ecological garden city was designed.And then, the basic rule of urban heat island was summarized.Bring forward some advices to study urban heat island to satisfy the demand of building a national ecological garden city.Finally, according to the evaluate standard of national ecological garden city to study and obtain authoritative and exact evaluate result of urban heat island actuality.Through high resolute numeric model to execute experimental study, unfold the benefit and harm of special geographic environment such as hills and rivers in building national ecological garden city.In order to control urban heat island, the river wind and anabatic wind must be protected and utilized, which could strengthen the natural aeration of the city zone.