Abstract: The subtle traps of lithological type and stratigraphic type are found in Taibei sag of Turpan-Hami basin.The authors discussed the factors, conditions and features of these two traps, and evaluated the areas conformed to con-ditions of them,based on sandmud combination characters and their filling relations to the structures for each area ofTaibei sag. The result shows that these traps are difficult to be shaped in most part of the area,due to their special de-pendence on the geological factors. When some of the area are ready to be denied for poor potentials,predictions forfinding potentials for the two types of subtle trap in Taibei sag are made again.