Abstract: It is important to date the Quaternary volcanic rocks for understanding the neotectonic activities in Hebei plain. The 500.25 meter drill hole CK3 located near Haixing Country of Hebei Province revealed 4 layers of volcanic rocks. The 40Ar/39Ar age of the first stage of Quaternary volcanic rocks is 2.36±0.05 Ma. Combined with the magnetostratigraphy of CK3 core, the time of volcanic activities in Hebei Plain should be about 1.3 Ma, 35?70 ka and 10?15 ka, respectively.