Abstract: There exist exstensive thick Pleistocene (Q3) loess on the dam foundation of Daliang Reservoir for diversion of Huanghe River into Shanxi Province.Statistic of large number of test data,study of initial subsidence presure and subsidence coefficient peak,and SEM study of microstructures of the loess from different deoths indicate that the subsidence of loess is mainly controlled by void structure.The subsidence rate decreases with increasing burial depth of loess and gradual transition of void structure to local void or mossaic void structure of the loess.It provides a basis for engineering treatment of the otess on the dam foundation.