On the basis of field investigation and laboratory identification and analysis, the large-scope migration of desert-steppe in Loess Plateau about 450 ka BP was discussed. The data show that gypsum, represent desert-steppe environment developed in the early stage of the fifth loesss format ion in Shaoling tableland of Chang an and Bailu tableland of Xi'an on the southern edge of Loess Plateau, which shows that remarkable drying of climate and large-scope climatic migration toward south occurred in the area at that time, and climate zone migrated about five degrees in latitude, and desert-steppe and more wild environment distributed widely in Loess Plateau. The development of gypsum also shows that climate changed from monsoonal climate to non-monsoon climate in Loess Plateau, which was a change in character, and this area had been not effected by summer monsoon, and in the early stage of the fifth loesss formation, was in non-monsoon climate environment at that time.