This paper presents a detailed study of the eruption ages and time series of activity of volcanoes in the Wudalianchi area. Based on the fact that the fine crystalline olivine in the samples contains excess argon, analyses and corr elat ion are made of the available data to evaluate their usability. Consequently, th e effects of olivine content on the age data have been known: when the content o f fine crystalline olivine in the samples is around 5%, the effecting degrees wi ll be below 5% for age data of about 200 ka. According to the available isotopic age data, the volcano swarms in the area are divided into 7 interals, i.e., 1.3 Ma, 0.9~0.8 Ma, 0.6~0.45 Ma, 0.38~0.24 Ma, 0.16 Ma, 0.09 Ma and 270 a, from whi ch it is known that the eruption intervals since the Middle Pleistocene should b e 70~80 ka.