The features of the abnormal sudden changes of ground tilt before earthquakes, statistical relationships between the duration of the sudden change to its peak value and the interval from the start point of the anomaly to earthquake occurrence and emperical relationships between the composite vector of the sudden change and the epicentral position are tentatively discussed in this paper. The conclusions are the following:
(1) Doubled time from the starting point of the sudden change of ground-tilt to its peak value plus a constant equals the interval between the starting point and occurrence of earthquake.
(2) The composite vector of the sudden change of ground tilt directs mostly to the epicenter, or back on the opposite direction.
(3) Generally the longer the duration of the abnormal sudden change of ground tilt and the bigger the abnormal change, the greater the magnitude of earthquake after the anomaly.