Drought seriously impacts the production of wheat (Triticum aestivum L.), while the exploitation and utilization of genes for drought tolerance in wheat is insufficient. Leaf wilting is a direct reflection of drought tolerance in plants. We identified a drought induced wilting 1 (diw1) mutant by screening a mutant library of wheat Aikang 58. Through map based cloning, DIW1 gene was proved to encode a protein phosphatase 2C (TaPP2C70). A gain of function mutation enhances the protein phosphatase activity of TaPP2C. Phenotypic analysis of overexpression and CRISPR/Cas9 mutant lines demonstrated that DIW1/TaPP2C70 is responsible for ABA-dependent drought response. TaSnRK1.1, an interactor of TaPP2C70, was identified by yeast two-hybrid (Y2H) screening, and the interaction between TaPP2C70 and TaSnRK1.1 was verified in vivo and in vitro. Further studies showed that TaPP2C70 dephosphorylates TaSnRK1.1 and inhibits ABA signaling. Association analysis suggested C-terminal variation of TaPP2C70 was highly correlated with the canopy temperature, seedling survival rate under drought stress, and protein phosphatase activity. And the favorable allele had been positively selected in Chinese breeding history. This work not only benefits us to understand the molecular mechanism of wheat drought tolerance, but also provides elite genetic resources and molecular markers for improving wheat drought tolerance.