The Cretaceous of the Kuqa Depression and Southwest Depression in the Tarim Basin is very thick and consists of many rock types,such as clastic rocks，evaporites and carbonate rocksThere are many kinds of sedimentary facies,including continental facies，marine facies and transitional facies，and the continental clastic facies is dominant Kuqa Depression and Southwest Depression were separated basins in the Early Cretaceous，but they had nearly the same characters of continental clastic sediments They both were mainly developed into alluvial depositional systems with an obvious similar distribution of facies belts and a similar development of reservoirCorresponding to the asymmetry of foremountain faulted basin,the alluvial fan-fan delta depositional system and the braided fluvial delta depositional system were developed at the steep slope of the lacustrine basin，and the fluvial delta depositional system were developed at the ramp slopeThe alluvial fanfan delta depositional system was composed of the alluvial fan, the fan delta plain and the fan delta front, etcThe braided fluvial delta depositional system included braided fluvial delta plain and braided fluvial delta front, etc Reservoir rocks were mainly developed in the braided channels, subaqueous distributary channels and the distributary mouth bars in fan delta or braided fluvial deltaThere are highquality reservoirs in the Kuqa Depression and Southwest DepressionThe reservoir sandbodies are thick and widely distributedThe development of alluvial depositional system indicates that the reservoirs of the Cretaceous may be extensively distributed in the Tarim BasinThe exploration achievements made in Kashi Sag and Yingjisu Sag in recent years greatly broaden the field of explorationThe Cretaceous is becoming one of the important exploration targets in the Tarim Basin, and it shows better prospect of petroleum exploration