Abstract: Zircon U-Pb dating reveals that the K-feldspar granite and granodiorite in Quruqtagh on the northern margin of the Tarim block crystallized at 630.1±1.3Ma and 630.6±1.3Ma, respectively. Zircon Hf isotopes indicate that these granitic rocks were mainly derived from partial melting of old andestic-basic crust with possible involvement of basaltic magma from mantle sources. Based on a comprehensive analysis of the Neoproterozoic igneous activities in Tarim, the authors argue that the 650~615Ma igneous rocks in Quruqtagh were the latest phase of the Neoproterozoic igneous activities and genetically related to the breakup of the Rodinia suppercontinent, i.e., they had nothing to do with the Pan-Africa orogeny. From Neoproterozoic to Cambrian, sedimentary sequences in Quruqtagh exhibited typical sedimentation features on a passive continental margin, which indicates that the Tarim block had never incorporated into the Gondwana Land.