Abstract: This paper briefly reviews the temporal and spatial characteristics of crustal deformation and its relationship with strong earthquakes in Chinese mainland based on geodetic observations. It also introduces the progress and understanding of extracting multi-scale crustal deformation characteristics associated with seismogenic process and various deformation anomalies before earthquakes in Chinese mainland. However, it is still insufficient that the effective basis for the crustal deformation can give the prediction of strong earthquakes in a clear time scale of 10 years and shorter. In order to promote the progress of continental strong earthquake prediction in a short time scale, it is necessary to effectively identify the process of strong source approaching earthquake in late seismogenic stage. Based on the analysis that the crustal deformation information observed by global navigation satellite system(GNSS) before several strong earthquakes, the crustal deformation state in the focal region of the late pregnancy earthquake could be transferred to the inelastic deformation state. Considering the factors such as the progress of observation technology, the possibility and related problems of the effective identification of the late pregnancy earthquake approaching to the strong source are discussed.