In order to improve the sustainable use of water and land resources in urban development, this study took Xi'an City as an example to construct the urban complex ecosystem model of “Social-Economic-Water resources-Land resources-Ecological environment”, based on the system dynamics method (SD) and compound ecosystem theory. By setting up three scenarios of economic priority, environmental protection and coordinated development, we analyzed and contrasted the trend of complex ecosystem in Xi'an from 2004 to 2025 under different scenarios. Moreover, the simulation analysis of the land and water resources utilization, economic and social development, and the ecological environment under the coordinated development program was conducted. The results showed that: the coordinated development scheme is the best plan for the utilization of water and land resources in Xi'an. After 2017, Xi'an will still face water shortage for a long time, and the water supply gap is large. In order to meet the urban water demand, it is very necessary to transfer water from other regions and to build new water source project. The area of construction land in Xi'an will increase year by year, and will increase to 914.70 km2 in 2025. The area of cultivated land will still be reduced year by year, and it will be reduced to 21.8546×104 hm2 in 2025. By promoting the construction of the water saving city, carrying out the intensive use of the land, developing the third industry and controlling the population growth, we can control the utilization of water and land resources in Xi'an. This study provides a basis for comprehensive planning and efficient utilization of urban water resources and land resources.