The construction of ecological city conforms to the ecological trend of the world, and it is a necessary way to promote the sustainable development of Chinese cites. The scientific ideas of choosing the construction of ecological city as the only strategy, understanding the purpose and important tasks of the construction, stressing the key factor of city space, and invoking the optimization of city open space system, should be established. The fundamental aim of the construction of ecological city is: urging the city ecosystem's structure and function to be reasonable and coordinated, realizing the city scale expansion and the connotation optimization by the new growth way, adjusting the city spatial structure and building the open space systems by the intensified way, realizing the high fusion of the city primarily nature environment with the artificial environment by the restoring way, and promoting the city to enter the condition of the sustainable development. The construction of ecological city in China should take the scientific principles of optimizing wholly the city-region ecological system, coordinating the relationship between the construction and the economical-social development, taking human beings as the basis,sharing equal profit, and adhering to the regional creativity. Under the condition of extremely arduous urbanization duty and city burden aggravates in China, it is really a grand project with rich times significance and great interest to the country and the people. We should improve the city ecological environment quality and give impetus to ecological city construction by scientific ideas and principles, from the very beginning.