Abstract: The chronological age of Shijiagou Formation is always controversial. On the basis of systematical summary of the stratigraphic division of Shijiagou Formation in Shandong Province, the authors in this paper have systematically sampled 11 profile outcrops of Shijiagou Formation in Penglai, Changdao and Wudi, and obtained 14 K-Ar ages and 2 ESR ages. Through the comparative analysis with previous dating data, it is found that Quaternary Pleistocene basalt is only exposed in Jieshi Mountain (0.87 Ma) in Wudi and Yingkou Mountain (1.51 Ma) in Beigou Town, Penglai City in Shandong, while other test ages are Neogene (9.24~5.02 Ma). The basalt strata in Penglai and Changdao areas mostly belong to the Yaoshan Formation in the Late Miocene (except for Yingkou Mountain in Beigou Town of Penglai City), while only a few belong to the Quaternary Shijiagou Formation. It is suggested that the basalt in Wudi Mountain and Yingkou Mountain of Beilinyuan in Penglai should be classified as Quaternary, and the Quaternary Shijiagou Formation exposed in other areas should be classified as Neogene.