Objectives: Lying at western Cathaysia Block and southern Qinzhou—Hangzhou junction，Ganzhou Basin develops a red clastic sedimentary rock system of early Late Cretaceous，of which the bottom clips a suit of basalt, these rocks are highMg and sodium. The highMg mafic volcanic rock represents the composition of the original magma. According to this study, and combining the achievements of the predecessors, we can Provide more accurate evidence about nature of source region and tectonic setting of these basalts, in addition to restrict the lithospheric mantle features of Cathaysia Block. Methods: Based on detailed observations of occurrence of Ganzhou Basin sodium and highMg Basalt in the field, we have studied the petrology, geochemistry, Sr—Nd—Pb radio isotope and O isotope of these basalts to discuss nature of source region and tectonic setting. In compare with achievements of the predecessors, we have discussed the lithosphere mantle features of Cathaysia Block. Results: The total rocks span a SiO2 range of 46.50%~48.13%，in addition，these rocks are highMg and sodium(MgO=15.47%~18.24%，Mg#=74~77，K2O/Na2O=0.22~0.39). Distribution pattern of REE is enriched in LREE and less obvious Eu anomaly，which show that the magma has not happen obvious plagioclase fractional crystallization. These rocks are enriched in LILE a little，such as Ta，Nb and Ti. Cr=235×10-6~617×10-6，Ni=157×10-6~493×10-6. They are similar to primary magma. Ba/Nb=13.51~23.18 and La/Nb=0.82~1.03，which show that source includes enriched mantle. Sr—Nd—Pb—O isotopes show that the area has the characteristics of EMII enriched mantle. Conclusions: these basalts in Ganzhou Basin have the primary magma characteristics, in addition, the genesis of them is related to the partial melting of the enriched mantle. In short，this paper presents the partial melting of the enriched mantle rock to explain the reason for source area，which offers proof of Cathaysia block lithospheric mantle type in Mesozoic Era. According to structure setting of Ganzhou basin in Late Cretaceous and diagrams，the basalt is formed in the withinplate extension environment，it is also related to subducting of PaleoPacific Plate.