The loess—paleosol sequences of the Chinese Loess Plateau provide one of Earth's most complete and intensively studied terrestrial records of climate change. However, the following questions are still controversial issues: 1.Where is the eolian source of the loess? 2. Is the provenance of the Quaternary loess different from the Tertiary Red Clay and does the provenance of the Quaternary alterative loess—paleosol sequences change? Here we apply single grain zircon U Pb age data for red clay, coupled with some previous data and single size zircon size to analyze the source of eolian deposits on the Chinese Loess Plateau. We conclude that the gobi (stony desert) in southern Mongolia and the adjoining gobi and sand deserts in China are the dominant source areas of the Loess Plateau, with a small portion coming from northern Tibetan Plateau, rather than mainly deriving from northern Tibetan Plateau and Qaidam Basin; the provenance of red clay is partly influenced by the close by bedrock, and zircon detrital of the Chaona red clay during 62~36 Ma partly derive from the Liupan Shan. The provenances of loess around 012 Ma, 086 Ma and 125 Ma don't change obviously, but the provenances of loess and red clay deposited at 26Ma and 36Ma changes obviously.