Abstract: A high-resolution sampling spacing 5cm in loess and 3cm in paleosol layers was finished for the 140-meter-depth classic loess profile in Luochuan, central Chinese loess plateau in the summer of 1993. Magnetic susceptibilities of all samples were measured in ‘Xi’an Laboratory of Loess and Quaternary Geology. We employ the magnetic susceptibility as proxy indexes of paleomonsoonal climate change during the past 2.5Ma. Based on the Milankovitch theory of Pleistocene ice ages, a preliminary time scale for this loess profile was set up. By comparing with the absolute magnetic reversal ages and orbital tuning time scale for Baoji loess section, it is proved that our time scale is useful for the paleoenviornmental study around this region.