A large number of Precambrian rocks are developed in the Alxa block. For a long time, the attribution of the Precambrian in the Alxa block has been controversial. The early Neoproterozoic gabbro was found in nuergong area of Alxa block for the first time, which provides new evidence for the attribution of Alxa block. Systematic petrology, zircon U-Pb geochronology and Lu-Hf isotopes of gabbros were studied. The zircon LA-IC-MS U-Pb ages of the two gabbro samples are 944 ± 7 Ma and 953 ± 6 Ma, respectively, belonging to the early Neoproterozoic. The results show that the SiO2 content of gabbro is 43.11% ~ 47.00%, MgO is 6.33% ~ 11.59%, TiO2 is 1.55% ~ 4.63%, which is a high aluminum subalkaline tholeiite series; Gabbro is rich in Rb, Ta, Zr, Ti and other elements, and depleted in Ba, Nb, Sr, Hf and other elements. It has a slightly right dipping REE distribution curve pattern, and the Eu anomaly is from weak negative to strong positive (δEu =0.84 ~ 1.65). The zircon Hf isotope ε Hf(t) is +2.2 ~ +6.6, and the single-stage model age (tDM1) is 1244 ~ 1426 Ma. The formation of gabbro is mainly controlled by the partial melting of asthenosphere mantle, and the parent magma is contaminated by crustal materials in the rising process. Through comparison, it is found that the gabbros developed in Alxa block are the product of a relatively common early Neoproterozoic extension event in the world, which may be related to the breakup of Rodinia supercontinent. The Precambrian evolution of Alashan block may be more related to the North China Craton.