Thelate Mesoproterozoic Dengxiangying Group in the western Yangtze Block is a rift- related sedimentary- volcanic sequence that is particularly important for the Precambrian tectonic evolution of the Yangtze Block. LA- ICP- MS zircon U- Pb dating of the Songlinping, the Zegu and the Chaowangping yielded zircon U- Pb ages of 1166±6 Ma, 1040±4 Ma and 1020±4 Ma, respectively. The geochemical features of Songlinping sandstone samples indicate a predominantly felsic (granitic) source for the detritus. The Zegu dacites have high Zr, Hf, Ga, and HREE contents and Ga/Al ratios, and high calculated zircon saturation temperatures, thus resembling A- type granitoids. In addition, these rocks have negative εHf(t) values (15. 1~9. 1), indicative of their derivation from partial melting of felsic continental crust. The geochemical discrimination diagrams suggest a continental rift setting for the Dengxiangying Group. Combined with previous studies, we concluded that the western Yangtze Block was located in an intra- continental rifting basin in a passive continental margin during the late Mesoproterozoic. An early- Neoproterozoic tectonic transformation from a continental- rifting basin to a compressional setting is suggested, and the Yangtze Block was in the peripheral rather in the center in the configuration of Rodinia.