Abstract: Well Tashen-1,drilled in Tarim Baisn in July 2006,is an ultra-deep scientific exploration well with its designed depth being 8000 meters and the completed depth achieving 8408 meters.It is drilled to probe into the quality,characteristics of reservoir development,and petroliferous property of the Cambrian built-up in the east margin of Akekule uplift.Various problems caused by well depth greatly increase the drilling risks.Based on employing reasonable casing programs,E-3000 electric drilling rig with the depth being 9000 meters,and different drilling technologies,optimizing drilling tools assembly,drilling bits,and drilling parameters,preparing and maintaining the properties of drilling fluid,and normalizing drilling operation,bore holes are better stabilized and the quality of well bores is kept well.After drilling,every casing of the well is set to their designated position,ensuring the high efficiency and securing of the cementing operation.The successful drilling and application of new drilling technology provide valuable experience for drilling other ultra-deep wells.