Abstract: The Tazhong (middle Tarim Basin) Low Arch is one of the sub-tectonic units of middle harimUplift. It is composed of the Tzl fault zone, the Tz north slope and the middle fault-horst zone.The razhong Low Arch is a long-term successive rise which has experienced 7 periods of evolution. The multi-period rising and subsiding brought up lots of reserve-seal assemblages and abundant traps.The multi-period regional unconformities and major faults provided excellent pathways and locations for petroleum migration and accumulation.The Tazhong Low Arch is favorable for petroleum migration and accumulation.The ordovician system has many petroleum reservoirs in a favorable position.The Tzl fault tectonic zone is the most favorable zone for petroleum accumulation with the Tz north slope as the second and the middle fault-horst zone as the worst.The Tzl fault tectonic zone is still the favorable prospect of future exploration.