Based on the zircon SHRIMP U-Pb analysis on 5 metamorphic rock samples collected from the Zongwulong tectonic belt, Northern Margin of Qaidam Basin, 80 magmatic zircon age dating results distribute from 510Ma to 420Ma. The 5 tested samples yield 206Pb/238U average ages of 437.8±2.7Ma(sample Qb-217), 440±3Ma(sample Qb-218),433.2±3.6Ma(sample Qb-219),497.1±3.5 Ma(sample Qb-225) and 464.1±4.2Ma(sample Qb-228), respectively, after corrected by 204Pb. These five 206Pb/238U average ages indicate the time of zircon crystallization and the enplacement time of the magma. The proliferation of Caledonia zircons shows that,magmatic and metamorphic activities related to massif discrete—aggregation existed during the Early Paleozoic period. The Zongwulong tectonic belt is a massif boundary between Central—South Qilian massif and Oulongbuluke massif. Thereby,Zongwulong tectonic belt is a composite orogeny with long term geological evolution processes and multi-phased tectonic events.Its structural rudiment formed no later than 497.1±3.5 Ma.Its tectonic framework established eventually in the Indo—Chinese period.