Studies regarding urban ecological land can provide scientific methods and information for decision-making in land resource use and planning. Urbanization level of Lanzhou City during 1999-2008 is evaluated using entropy method along with integrated urbanization index system. Furthermore, the supply and demand of urban ecological land was estimated based carbon-oxygen equilibrium theory. The coupling relationship be-tween urbanization level and ecological land supply and demand was investigated by applying grey correlation analysis. The results show that the grey correlation degree between economic-urbanization and ecological land supply and demand was the biggest, followed by population-urbanization. The changing trend of eco-nomic-population-urbanization was highly consistent to that of ecological land supply-demand.