The Zaibian mafic intrusion is located in the transition zone of the Yangtze craton and the south China fold system, where is the southwest of Jiangnan orogenic belt. The major elements results show that the samples belong to the calc-alkaline series, with the feature of poor K2O (0.03-0.29 wt %). The REE results of the samples show that the samples enrich LREE, with a higher total REE, and a weak or no Eu and Ce anomaly. The LILE (K, Ba, Rb) is tens times higher than MORB relatively, which is consistent with the intra-plate basalt; the HFSE is mid to weak of Nb. Sr-Nd isotopic studies show that the values of 87Sr/86Sr and 143Nd/144Nd range from 0.711097 to 0.712008, with a high Isr (t= 848Ma, from 0.710947 to 0.711726) and from 0.512413 to 0.512546, with εNd (848Ma) from +0.3 to +2.3), respectively. Zircon U-Pb age is 848 ± 15Ma, MSWD = 0.54, which indicating that the diabase was formed in the mid-Neoproterozoic. U-Pb zircon age, Sr-Nd isotopic compositions and geochemical studies have shown that the diabase was sourced from the depleted asthenospheric mantle, produced in the intra-plate extensional environment, belongs to the calc-alkaline basalt series, contaminated by the crustal material, and formed from the mantle plume, which made the Neoproterozoic supercontinent Rodinia breakup. This study supports the view that South China was located in the supercontinent Rodinia between the continents Australia and Laurentia in the Neoproterozoic.