The paleostructure of southwestern Qaidam Basin was extremely gentle during Paleogene and had palaeogemorphic characteristics with a shallow basin as well as a wide lake. Its geologic climate was mainly arid and semi-arid, which could result in strong weathering of provenance and provide abundant clastics for large-scale shallow water delta deposits. The paleo-water depth was within 10 m and the relative lacustrine level chang was quite frequent. All those mean that it has the paleogeography for the study area to develop the sediments of shallow water delta. The overall lithology of shallow water delta is characterized by middle-fine sandstone, siltstone, conglomerate or pebbly sandstone interbeded with brownish red mudstone. The particle size probability curve of sandstone mainly displays as two-section. The sedimentary structures of strong water dynamics as well as bioturbations are plentiful in the sandstones. The sand bodies morphology of shaollow delta in study area can be divided into arborization, cuspate and sheet shapes according to the coupling relation of climatic change, material source and so on, which roughly correspond to the shapes of E_3~1, E_3~2 and N1. The distribution of Paleogene sand bodies in the study area is controlled by the five large-scale fracture slope break zones and the derived flexure slope break zones, such as Qigequan, Hongliuquan, Alaer, Kunbei and XI, which can be divided into inverse source type and following source type. On that basis, the sandbodies controlling model by the structure slope zones of Paleogene formation in Southwestern Qaidam Basin can be established.