Abstract: On the basis of analysis on the regional evolution history,seismic factes and sedimentary factes of Qiaoxiaoergai structural belt in Northern Bachu arch,the paper pointed out that Cambrian-Ordovician is located in the local palaeohigh of the platform and its frontslope reef flat factes and slump sedimentary factes, and since the Cambrian-Or-dovician epoch,it has been a favorable orientational zone for oil and gas migration. It also made an analysis on the favorable and unfavorable factors for formation of reservoirs and recommended the target zones for exploration.

Key words: Tarim Basin, Bachu, arch, regional structure, evolution, seismic factes, sedimentary factes, reservoir formation