Xiatianba granite is located in the northeast of Yunnan province, the mass fraction of SiO2 is 71.1%~78.15%, and Al2O3 is 11.55%~14.90%, the value of A/CNK is 0.94~1.25(1.15 on average). These characteristics indicate that Xiatianba granite belongs to peraluminous S-type granite. The value of REE contents of the rocks ranges from 259.71×10-6~804.60×10-6(402.54×10-6 on average), and the ratio of LREE/HREE is between 4.12 and 10.28, which suggest that LREE is richer than HREE. The granite has a strong negative Eu anomaly(δEu=0.04~0.07), the enrichment of LILE(Rb、Ba、Pb、U) and depletion of HFSE(Nb、Ta、Sr、Ti) show that the granite is partial melting of the crust. Zircon from Xiatianba granite are used in LA-ICP-MS U-Pb dating, yielding a weighted mean 206Pb/238U age of 769±4.4 Ma, which is not Early Paleozoic as recognized before and consistent with the time of breakup of Rodinia supercontinent in the western Yangtze block. Xiatianba granite was formed in extensional setting, it was caused by the mantle plume activity in the breakup of Rodinia supercontinent during the continental rift environment. This is confirmed by the southwestern margin of Yangtze Block in the Neoproterozoic rift environment affected Dongchuan area of northeast Yunnan province.