Abstract:With the Tuojiawan sediment profile as study objectives, we analyzed their macroscopic structure, sedimentological characteristics and physicochemical properties, and obtained their formation time using OSL dating. Based on the field observation and indoor laboratory data, this study also established the stratigraphic sequence of the loesspalaeosol in the Upper Reaches of Hanjiang River valley. OSL datingbased stratigraphic chronology study reconstructed the change history of the Upper Reaches of Hangjiang River since the last 55 ka BP. The results suggest that four sequences developed in this area. Terrace I of Hangjiang River formed around 55 ka BP, immediately followed by continuous eolian sediments. The stratigraphic palaeosolloess sequence of the Tuojiawan profile from the bottom to the top includes: loess L1L3 (550~285 ka BP)→ palaeosol L1S2 (285~245 ka BP)→ L1L2 (245~230 ka BP)→ palaeosol L1S1(230~210 ka BP)→ L1L1 (210~115 ka BP)→transitional loess Lt (115~85 ka BP)→palaeosol S0(85~30 ka BP)→recent loess L0(30~0 ka BP). The Malan loess records four warmwet periods occurring at 410~445 ka BP, 340~375 ka BP, 245~285 ka BP and 210~245 ka BP. Among them, the last two periods gave rise to the formation of palaeosol L1S2 (370~296 cm) and paleosol L1S1 (276~230 cm). During the megathermal period (85~30 ka BP), the upper Hangjiang river was not always the most warmmoist climate since the last glaciation, but intermittently, and relatively transient, relatively cool and wet climate occurred at 5~6 ka BP.