Abstract: On the basis of data recorded for many years by the network of geomagnetic observatories in China, the anomalous features of appearance time of the minima of diurnal variations (i.e. low-point time) of the geomagnetic vertical component and the variation of their spatial distribution (i e. phenomena of low-point displacement) have been studied. Such rare phenomena of geomagnetic anomalies are an objective reality, being well-correlated with the occurrence of earthquakes. It has been found that most earthquakes occur in the vicinity of the boundary line of sudden change of the low-point displacement and generally within four days before or after the 27th or 41st day counting from the day of appearance of the anomaly.The low-point displacement is one of the complicated geophysical phenomena which is affected by many factors and its mechanism is still under study.