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Observations of all-sky imaging, geomagnetic Field, Pi2 Pulsation from Zhongshan station and IMF data from Wind satellite have been used to investigate 7 cases of nightside arcs intensification and decaying in high latitudes. The characteristics of auroral arcs are as follows: All of arcs intensify briefly, then decay, and last for 10−20 min; the arcs nearly align along the Sun-Earth direction with pronounced duskward drift; most of the arcs occur after the interplanetary magnetic field (IMF) turns southward corresponding to the substorm growth or expansion phase, and IMF Bx > 0, IMF By 0 which favors magnetic reconnection in the southern lobe of the magnetotail, the arc decaying may be attributed to southward IMF Bz, and the duskward motion of the arcs may be driven by the effect of the IMF By component on the motion of the reconnection site.