Mighan watershed is a closed basin with playa in its center at the present. This playa is an important playa which cantains Na2SO4 mine. Mighan watershed has formed several geomorphological unites. The main unite of it is lowland region or playa from around to center of playa; there are regions such as sandflat, Mudflat and salt flat. We drilled eight small test pits in different flates and identified various regions in surface and subsurface. Based on test pit investigation, it denoted Na2So4 (as Mirrabellite and Glouberite Minerals) is recognized in crystalline phase and porefilling of sediment in saltflat. The determination of various environments in playa is the subject of this study.