Abstract: According to the principle of earthquake stress triggering theory, based on the principle of fault interaction, the authors studied Coulomb failure stress change of earthquakes with magnitude above 6 in the Southeast China area.The preliminary result indicates that subsequent strong earthquakes mostly occurred in the tress increasing area caused by the previous earthquakes.It proves the strong earthquakes are interactive, that is to say, strong earthquakes are prepared and occurred in groups.It might be of practical significance in the prediction of earthquake risk areas.

Key words: Earthquake stress triggering, Coulomb failure stress, Seismicity in groups