The Jining volcanic field located in the southern margin of the Mongolian plateau and the western North China Block consists of four rock types: quartz tholeiite, olivine tholeiite, alkali olivine basalt and basanite. These rocks have a wide range of K-Ar ages from ~36 to < 0.2 Ma. The early volcanism was voluminous and dominated by flood-type fissure eruptions of tholeiites, whereas the later phase was represented by sparse eruptions of basanitic lavas. Thirty-six samples analyzed in this study show a wide range in SiO₂ contents from 44% ~ 54%. They all are sodium-rich and high-Ti basalts that, however, show marked isotopic variations between two end-members: (1) tholeiites that have higher ⁸⁷Sr/⁸⁶Sr of 0.7048 ~ 0.7052, and lower εNd of -0.8 to -2.4 and Pb isotope ratios (²⁰⁶Pb/²⁰⁴Pb of 16.9 ~ 17.2, ²⁰⁷Pb/²⁰⁴Pb of 15.3 ~ 15.4 and ²⁰⁸Pb/²⁰⁴Pb of 37.1 ~ 37.7); and (2) basanites that have lower ⁸⁷Sr/⁸⁶Sr of 0.7035 ~ 0.7044, and higher εNd of +1.3 to +4.9 and Pb isotope ratios (²⁰⁶Pb/²⁰⁴Pb of 17.7 ~ 18.0, ²⁰⁷Pb/²⁰⁴Pb of 15.4 ~ 15.5 and ²⁰⁸Pb/²⁰⁴Pb of 37.8 ~ 38.2). Alkali olivine basalt that occurs as a subordinate rock type is geochemically similar to the basanites, but isotopically similar to the tholeiites, characterized by the highest ⁸⁷Sr/⁸⁶Sr ratio among the three basaltic suites, coupled with a low Nb/U value (~33).