Modeling land use scenarios change and its impact in typical regions are helpful to investigate the interactive mechanism between land use system and terrestrial ecosystem, and optimize land use pattern and reduce potential ecological risk in the process of future land use. A System Dynamic (SD) model aims at modeling land use scenarios change and assessing its ecological impact in the northern China in the next 50 years is developed in this paper. The accuracy assessment with historical data covering 1990 to 2001 indicated the SD model is reliable. After the different "what-if" scenarios controlled by GDP, population, market and technology advancement were built, the different land use scenarios changes in the northern China from 2000 to 2050 were simulated with their ecological impact assessment. The result suggested that such factors as GDP, population, market and technology have good relationship with land use structure change in the northern China. It also indicated that such measures as strictly controlling population growth, importing proper amount of grain from other regions in addition to increasing per unit area grain yield to keep supply-demand balance in the region, and improving agricultural technology are the guarantee to the regional sustainable development with fast economic growth and obvious land use structure improvement at the same time.