Abstract: In this paper, based on some predicting criteria of seismicity, such as preparation gap,seismic velocity ratios, spatial scanning of values, activity of earthquake swarm, N values, b values, C values etc., the characteristics of seismicity before the Datong-Yanggao Ms 6.1 earthquake are analyzed.The results show that, the anomalies of these criteria aboveme-tioned occurred in succession in the later six months in 1986.It is pointed out that the dura-tion between the imminent earthquake appeared in the later period of the prepatation gap and the mainshock is longer than that obtained in some earthquake cases.Finally in this paper,we present a seismically active belt from south Yellow Sea, through Sheyang to Datong,which is possible to be a important zone in which some moderate and strong earthquakes may occur next years.