Currently, in northern China, the impact of aridification on land system is not very clear, which would, to some extent, restrict the rational development and utilization of land resources. Therefore, based on the principle and method of system dynamics (SD), a SD model aims at simulating land use changes in northern China under different aridification scenarios and designed socio-economic status is developed in this paper. The accuracy assessment with historic data covering 1989 to 2001 indicates the SD model is helpful and reliable to understand the complex change process of land use system. The aridification scenarios in the next 30 years are defined as three types, from the reversal of aridification, gradual aridification to the acceleration of aridification with the increment of aridification degree. The results suggest that, in northern China, future aridification has great impact on the water resource, leading it to decline from 468.6 to 388.8 million m3 under different aridification scenarios. In other words, water resource is gradually becoming a rare resource restricting regional sustainable development. Furthermore, the results show that, under the pressure of population growth and economic development, the construction and traffic land will expand obviously and the conflict between cultivated land and construction and traffic land will be prominent. In all, in the future development, such issues as how to arrange land use structure and pattern rationally, and how to adapt to the pressures of climate change and socio-economic development together will be the main problems which would be faced and should be solved in the regional sustainable development in northern China.