Weinan section consists of Holocene soil SO, last glacial loess L1, and last interglacial soil S1, furtherly L1 can be subdivided into three layers of loess (L1-1, L1-3, and L1-5), and two layerS of weakly developed soil (L1-2 and L1-4). Based on studying the content variations of Carbonate, free Fe2O3, and the total organic content in Weinan section, the environmental evolution of this region has been discussed over the last glacial-interglacial cycle. Our results indicate that the chemical parameters can be ed as climatic proxy data, and the variations of these indexes reflect the cyclic nature of the Quaternary climatic change. In addition, the climatic records of Weinan section can also be correlated with that of the marine oxygen isotope records, so the environmental evolution of the Loess Plateau is also consistent with the global climatic changes. The unexpected finding is that the climatic curve of L1-5, which can be correlated with stage 4 of marine oxygen isotope records, consists of three troughs and two sandwiched peaks, and may suggest the existence of the second-order warmcold oscillations of this period.