Abstract: Da ta processing at the center for the Crustal Movement Observation Network of China is introduced in this paper, with the emphasis on the GPS (Global Positioning System) data processing . Therefore the observation system of the project and the data center are introduced at first. Data stream, methods and software used at the data center in GPS data processing for crustal movement are described in detail.Selection of solutions, estimation of accuracy, analysis of displacements, strain and time series of displacement is discussed. The results of crustal movement obtained from fiducial network from Sep. 1998 to Nov . 1999 are analyzed as well as the displacement of various fiducial stations, strains in different parts of the network and the time series of displacements of weekly solutions of the fiducial stations. During this period, the crustal movement in the eastern part of China is relatively small and stable; in relation to the eastern part of China the southwestern part moves northeastward and is compressed in NNE direction; the northwestern part moves northwestward, and the Yunnan region moves southward. The North-south Seismic Belt in the middle part of China is a belt of strong shear deformation. The result shows that the northward push by the Indian Plate has played the dominant role in the crustal movement in China's mainland.

Key words: GPS, Observation network, Crustal movement, Data processing, Earthquake prediction