Tibetan wheat, grown under high-altitude environmental constraints, shows an unknown adaptation mechanism. This study presents a draft genome sequence of Tibetan semi-wild wheat (Zang1817) and re-sequences 245 wheat accessions. High-altitude environments reshape wheat genomes, with Tibetan wheat accumulating high-altitude adapted haplotypes. Tibetan semi-wild wheat is identified as a de-domesticated form of Tibetan landrace, with two loci (a 0.8-Mb deletion including *Brt1/2* homologs and a region with *TaQ-5A*) responsible for rachis brittleness during de-domestication.
