The intermediate basic volcanic rocks in the Huichang area of southern Jiangxi province are characterized by : high total alkalis,enrichment of K2O,low TiO2 content, low iron content and the enrichment of LREE and LILE elements. In combination with the mineralogical features such as the appearance of orthoclase rims along the plagioclase boundary and the existence of orthoclase microcrystals in the groundmass,it is identified to be shoshonitelatite association and belong to typical interplate shoshonitic volcanic rock series. The RbSr isochron age of the Huichang shoshonite series (HSS)is 107.3±2.3Ma. The SrONdPb isotope compositions of HSS are characterized by the follows: distinctive high initial Sr isotopic ratios (ISr=0.7098~0.7115): lowδ18O value (5.3‰~7.0‰); intermediate initial Nd isotopic ratious (εNd(t)=-0.61~-3.60); enrichment of radiogenic lead ((206Pb/204Pb)i=17.32‰~18.29‰, (207Pb/204Pb)i=15.34~15.65, (208Pb/204Pb)i =37.51~38.60). The HSS have obvious Dupal anomaly(Δ7/4Pb=-7.8~+16.8,averagely +5.42); Δ8/4Pb=27.3~97.3 (averagely 68.04); ΔSr=96.2~114.1 (averagely 104.3)). The SrO, SrNd, SrPb, PbPb relationships of HSS strongly suggest a mixing source of the depleted mantle endmember with the lithosphere enriched mantle endmember. According to doublevariation and twocomponent (SrNd) mixing equation, calculation shows that the depleted mantle endmember and the lithosphere enriched mantle endmember are about 50% for rockforming materials of HSS. The exisitence of the Huichang Early Cretaceous shoshonitic volcanic rock belt implies a major extensional tectonic event during the Late Yianshanian period