Abstract: SIMS U-Pb dating and CL images have been done for zircons of garnet peridotite from Bixiling, southern Dabie. The C1 images reveal that most zircons have core-rim texture. The cores show igneous zircons characteristics. The rims may be recrystallized during ultra-high pressure metamorphism. Thirteen points were dated within seven zircons. A1l the points have The th/U ratios of 0.85～2.13, and ten of them ≥1.5. These suggest that most zircons come from the garnet peridotite, for it has positive Th anomaly in primitive mantle normalized pattern. Except for 4 points, the other nine analyses define a chord intersecting the concordia curve at 824Ma and 254Ma respectively. According to the zircons’ CL images, the upper intercepted age represents the magmatic protolith age, the lower intercepted age defines the metamorphic event. The protolith of Bixiling garnet peridotite-eclogite massif was formed at 824 ± 39Ma, and experienced UHP-metamorphism at 254±38Ma. Some xenocryst zircons have been found. Their ages are older than that of protolith of the Bixiling massif. These zircons may come from the crustal rock that was contaminated during the magmas rising.