Based on a lot of outcrops investigation, cores observation and well logs analysis, sandy mudstone member of Kalashayi Formation is divided into the standard typeⅠ sequence with a complete transgressive-regressive cycle. It corresponds to sedimentary strata of III-grade Sea-level cycles in Tarim Basin. Sandy mudstone of Kalashayi Formation is composed of lowstand system tract (LST); transgressive system tract (TST) and highstand system tract (HST). The lowstand system tract is made of alluvial fan deposit system. The transgressive system tract is mainly composed of fan delta, tidal flat, lagoon, evaporite flat and restricted platform.