In this paper some abnormal phenomena of the ionosphere which occur before and after great earthquake have preliminarily summarized. It is shown that the abnormal disturbances of the ionospheric form are a general phenomenon when earthquake is approaching and, secondly, there exist unusually temporal and spatial disturbances of "highpoint displacement" for F layer. They may associate with the nonuniform "electron cloud" of the ionosphere locally, formed and with the geomagnetic field and the geoelectric field as well as the electric properties on the surface. Further observations and studies on them would be helpful to estimate the region and approaching time of earthquakes. The relationship between the ionosphere and geomagnetic field and the earthquake are also briefly discussed. It is pointed out that the relationship may be due to the match effect of geomagnetic field.