The Paleolithic archaeological record of the Tibetan Plateau is crucial for understanding human ecological and genetic adaptation to life in high altitudes. Recent work on the Tibetan Plateau has documented hominin occupations by Denisovans at Baishiya Karst Cave (BKC) from at least ca. 160, and again around 100 and 60 thousand years ago (ka), followed by modern human occupation at Nwya Devu (ND) around 30–40 ka. However, with the exception of these two geographically distinct sites, there are very few Paleolithic sites with secure stratigraphy and reliable dates on the Tibetan Plateau. Thus, the spatial and temporal history of Paleolithic hominin occupation of the Tibetan Plateau remains poorly understood. Here we report a newly discovered well-stratified and well-dated Paleolithic site, Jiangjunfu 01 (JJF01), from the northeastern margin of the plateau. Optical dating of sediments from cultural layers shows that the site was occupied by hominin who employed simple core-and-flake technology, during warmer interglacial environments ∼90–120 ka. To date, JJF01 is one of the three oldest archaeological sites with secure stratigraphy and reliable dating from the Tibetan Plateau, further confirming that hominins, potentially Denisovans, occupied and inhabited the highest region of our planet at least by the early Upper Pleistocene.