Abstract: In this study, paleoflood slackwater deposits (SWD), loess and aeolian sand were surveyed and sampled in the middle reaches of the Yarlung Zangbo River valley in the Tibetan Plateau in China. Their macroscopic characteristics were observed and sediment experimental analyses (i.e., grain size, magnetic susceptibility and geochemical elements) were conducted. The primary goal of the study is to summarize the sedimentological identification marks of the paleoflood SWD in the middle reaches of the Yarlung Zangbo River valley in the Tibetan Plateau in China. Results showed that the SWD trapped in the Zangmu profile (ZM), Langxian profile (LX) and Milin profile (ML) all demonstrated horizontal wavy lamination with uniform structure and its macroscopic characteristics are obviously different from those of the aeolian deposits (e.g., loess and aeolian sand). The grain size composition of the paleoflood SWD, loess and aeolian sand are generally coarse, mainly fine sand (>0.063 mm). Among them, the grain size of the aeolian sand is obviously coarser than that of the paleoflood SWD and loess. The sortability of the paleoflood SWD is the best among the three sediments, followed by loess, and aeolian sand in the middle reaches of the Yarlung Zangbo River valley in the Tibetan Plateau in China. The reason is that the paleoflood SWD is a suspended sediment sorted by water. The higher magnetic susceptibility content of the paleoflood SWD is probably related to the increase of ferromagnetic minerals in SWD due to the surface scouring of the middle reaches of the Yarlung Zangbo River valley by floods. The grain size characteristics, major and trace element contents of the paleoflood SWD are close to those of the loess in the middle reaches of the Yarlung Zangbo River valley in the Tibetan Plateau in China. However, there are obvious different occurred in the grain size characteristics and major and trace element contents between the paleoflood SWD and aeolian sand. These suggested that the sediment provenance of the paleoflood SWD may be closely related with that of the loess in the middle reaches of the Yarlung Zangbo River valley in the Tibetan Plateau in China.