In the past more than ten years, distribution and prediction of lowstand sandbodies of LST had been put too much emphasis on during sequence stratigraphy research and petroleum exploration in continental faulted basins. As a result, petroleum exploration of highstand sandbodies of HST was directly restricted. Erlian Basin is located in the north-midland of Inner Mongolia Autonomous Region of China and is composed of many small faulted lacustrine basins of Early Cretaceous. In general, highstand delta system is well developed and formed the main sandstone reservoir in the gentle slop of faulted lacustrine basins. The petroleum exploration practice shows that highstand delta system that developed widely in gentle slopes, together with specific structural settings, can made many types of play and favorable petroleum accumulation zone.