Abstract: Suxiaodi profile is at the west bank of the Qiong Tailan river, in the southern side of Mt．Tumul, Tianshan Mountains．The profile is characteristiced by the alternation of Loess layers with baked soil layers．Based on the analyses of the profile, some conclusions is made out bellow：1．loess deposition in this region at last began in 7500 years B．P．2．The baked soil layer was the forest soil before it was producted by the forest fire, The loess layer and the baked soil layer represent the dry environment and relative moist environment, respectively．The relative moist periods in the scale of 10³-10² years appeared around 6580 , 5730, 4810, 3545, and 715 years B．P and the relative moist period and the dry period the scale of in 10³ years is divided at 3500 years B．P．3．The clim－ atic fluctuations from 7000 to 3500 years B．P．indicated the unsteadibility of the optemum.