This paper has studied the sedimentary environments facies and depositional system of the Middle-Upper Triassic Huangmaqing Formation in Anhui and Jiangsu Provinces, China. On the basis of sedimentary structures and their genetic types, we have recognized eight lithophases in the profiles of Huangmaqing Formation; Lithophase 1 Grey, greyish green and brownish grey claystone intercalated with dolomitic silty claystone, with marine fossils; Lithophase 2 Greyish purple sandy coarse siltite, siltite and clay siltite, with marine brackish water fossils; Lithophase 3 Grey, greyish green very fine to fine quartz sandstone and coarse siltite, with marine fossils; Lithophase 4 Greyish purple and purplish red silty claystone and clay siltite with fresh water fossils and plant fragments; Lithophase 5 Greyish purple coarse siltite, siltite intercalated with clay siltite, with scours, small-scale cross bedding and climbing ripple bedding; Lithophase 6 Greyish purple to greyish brown fine feldspathic quartz sandstone of lithic quartz sandstone, with medium-large scale cross bedding; Lithophase 7 Greyish purple siltite, clay siltite and silty claystone bearing calcite nodules, with paleosol characteristics; Lithophase 8 Greyish purple, brown lenticular fine conglomerate with scour surfaces; According to the sedimentary sequence and lithophase association of the succession, we consider that Huangmaqing formation formed a large fluvio-deltaic depositonal system, and its depositonal tectonic setting is a foreland basin. Depositional environments shown in the succession include prodelta, delta front consisting of delta front sand, mouth of distal bars and interdistributary bays, and delta plain consisting of fluvial distributary channels, natural levees, crevassing splays as well as floodplain and lake settings.