Abstract: The study of the composition and evolution of the Precambrian metamorphic series such as Xinghudukou Group in northeastern Da Hinggan Mountains is critical for determining the tectonic attribute of Ergun massif and Xing'an block, and thus is one of the hotspots of recent studies of northern Da Hinggan Mountains. Based on the U-Pb dating results of the detrital zircons from two-mica-quartz schist and the magmatic zircons from migmatite, the authors hold that the Xinghuadukou Group in the Shihuiyao-Mingzhi Mountain of northern Heihe area is not the Precambrian metamorphic rock, but is a tectonic complex composed of early Paleozoic sedimentary (or metamorphic) rocks and Late Paleozoic magmatic rocks. The dating results of the magmatic core of detrital zircons from two-mica-quartz schist show 7 age groups mainly, i.e., 401-427 Ma, 442-448 Ma, 473-517 Ma, 639-714 Ma, 757-818 Ma, 896-933 Ma and 1704-1751 Ma, in which the 473-517 Ma group exhibits most obvious peaks of detrital zircons and is consistent with the early Paleozoic magma event such as the island arc volcanic rock from the Duobaoshan Formation, and the other age groups have also been reported in many places in northern Da Hinggan Mountains. These characteristics suggest that the provenance was complex, composed of not only Proterozoic rocks but also Paleozoic rocks, with the early Paleozoic magmatic rocks being the main source. So the protolith age of the two-mica-quartz schist is the Paleozoic and might be sfter 416 Ma, as shown by the minimum peak age of detrital zircons. The considerable Proterozoic detrital zircons from the schist suggests that there indeed exists Precambrian basement in Ergun massif or Xing'an blocks. The migmatite outcropped in the Mingzhi Mountain is the mylonitized granite actually caused by the dynamic metamorphism, and it has a ²⁰⁶Pb/²³⁸U weighted average age of (304.5±3.1) Ma, which reflect the granite formed during the Late Carboniferous. The granite was part of the estern margin granite belt in of Xing'an blocks during the late Paleozoic.