Helium (He) and Argon (Ar) isotopic compositions of the Tertiary basic igneous rocks were determined by the high temperature melting extraction method. The selected samples for the studies included al-kaline basalts and diabases from the Jiyang basin,and the surrounding Shanwang and Qixia outcrops in the Shandong Peninsula,eastern China. The results show that the Paleogene basalts and diabases from the Jiyang basin yielded a wide range of P4 PHe abundance of (73.70-804.16)×10 P-8 Pcm P3 P STP·g P-1 P,with P3 PHe/ P4 PHe ratios of 0.374-2.959 Ra,which was lower than the MORB but evidently higher than the con-tinental crust value. The Neogene alkaline basalts from the Jiyang basin,Shanwang and Qixia outcrops have variable P4 PHe abundances ((42.34-286.72)×10-8 Pcm P3 P STP·g-1 P),and “continental crust-like” P3 PHe/ P4 PHe ratios (0.013-0.074 Ra). All of them contain atmospheric-like P40 PAr/ P36 PAr ratio (395.4-1312.7),reflecting the mantle sources with air components. Their low P3 PHe/ P4 PHe ratios are interpreted as the enrichment of the radiogenic P4 PHe mainly inherited from the mantle. He and Ar systematics show the mixing of MORB-type,air and a P4 PHe enriched member in the mantle source,suggesting that these igneous rocks originated from the depleted asthenospheric mantle mixed with an EMI component. Therefore,the present He and Ar isotopes do not support the viewpoints that the Cenozoic igneous rocks of Eastern North China were the products of mantle plume(s) activities. The selected samples for the studies include al-kaline basalts and diabases from the Jiyang basin, and the surrounding Shanwang and Qixia outcrops in the Shandong Peninsula, eastern China. The results show that the Paleogene basalts and diabases from the Jiyang basin yielded a wide range of P4 Ph abundance of (73.70-804.16) × 10 P-8 Pcm P3 P STP · g P- 1 P with P3 PHe / P4 PHe ratios of 0.374-2.959 Ra, which was lower than the MORB but evidently higher than the con-tinental crust value. The Neogene alkaline basalts from the Jiyang basin, Shanwang and Qixia outcrops have variable P4 PHe abundances ((42.34-286.72) × 10 -8 Pcm P3 P STP · g-1 P) and “continental crust-like” P3 PHe / P4 PHe ratios (0.013-0.074 Ra) like P40 PAr / P36 PAr ratio (395.4-1312.7), reflecting the mantle sources with air components. Their low P3 PHe / P4 PHe ratios are interpreted as the enrichment of the radiogenic P4 PHe mainly inherited from the mantle. He and Ar systematics show the mixing of MORB-type, air and a P4 PHe enriched member in the mantle source, suggesting that these igneous The origins of He and Ar isotopes do not support the viewpoints that the Cenozoic igneous rocks of Eastern North China were the products of mantle plume (s) activities.