Kaifeng City, one of China ’s "seven ancient capital cities"and an important member of "Zhongyuan city croup", plays an important role as the regional central city of East Henan province in Henan's urban system City open space is a huge container regulating and controlling urban ecosystem In order to bring Kaifeng City into the situation of sustainable development, it is necessary to improve the construction of Kaifeng ecological city by means of optimizing open space system On the basis of the discussions of the significance and requirement of the construction of ecological city and the necessity of the optimization of city open space system, this paper analyses Kaifeng City ’s salient features and new developing ways, and raises theoretical basis and principles for the optimization of Kaifeng City ’s open space system The overall optimization of Kaifeng City ’s open space system should proceed from two sides The first side is the readjustment of the spatial distribution structure of the city The new spatial distribution structure in Kaifeng City should expand effective area of open space system, strengthen supporting of open space system to ecological capacity of Kaifeng City,and build a base for the integration of the three circles in open space system The second side is the integration of the three circles in Kaifeng City ’s open space system The integration in each circle, and between the three circles, should make Kaifeng City ’s open space turning into an integrated and organic system, from which the construction of Kaifeng ecological city should obtain powerful spatial support The element optimization of Kaifeng City ’s open space system has two contents The first one is the optimization of green open space in the city The municipal government should adhere to the urban ecological norm, create high quality ecological, living and landscape environments, make wooded area, garden area and water area into a natural integration, make point, line and flat green land into an unitary system, thereby, establishing a green basis for the construction of Kaifeng ecological city The second one is the optimization of gray open space in the city The municipal government should adhere to the urban ecological norm, create high quality ecological, operational and building environments, make urbantraffic, outside traffic, square and parking area into a situation of coordinated development,makeroads from east to west, from south to north and loop roads into an unitary system, thereby, establishing a gray basis for the construction of Kaifeng ecological city