The Mei-yu season, characterized by persistent rainfall in the regions surrounding the East Asian coastlines, is crucial to the regional annual precipitation. With the progression of climate change, comprehending how Mei-yu precipitation (MP) will change in the future becomes paramount. Using a large set of high-resolution simulations, this study investigates MP's projected changes in the 21st century under different emission scenarios. Results indicate that MP will generally increase in the early 21st century and decrease toward the end of the century. The projected changes are tightly connected with the variations of the western North Pacific subtropical high (WNPSH). In the mid-21st century, the intensified monsoon trough tends to push the WNPSH northward, which in turn contributes to the northward movement of Mei-yu rain zones and more precipitation over the Japan regions, East China Sea, and the coastal area of eastern China. Afterward, the poleward advance of WNPSH becomes retarded due to the weakening monsoon trough. The northward movement of rain belts slows down, and reduced MP appears over the Japan regions and East China Sea. Compared to transient simulations, equilibrium simulations suggest a weaker MP reduction. These findings highlight the important role of monsoon in modulating Mei-yu precipitation under global warming.