Up to 3/4 of commuters take bus in Curitiba Brazil. It was chosen as the most livable city by the United Nations tied with Paris，Vancouver，Sydney and Rome. It has a good urban planning，good public transportation systems，good waste management and better environmental protection. What had happened during last 40 years？In simple word，Curitiba had solved the core problem of urban development：traffic，green space and waste disposal. This is an important reference to the most Chinese cities because of the same city problem in terms of a lower level of economic development.