Abstract: The greenhouse effect, caused by anthropogenic activities, has exerted a significant impact on the physical, chemical and bio-ecological properties of the global ocean. Among them, the changes in the Indian and Pacific Oceans (Indo-Pacific) are particularly significant and pose a serious threat to the warm-water coral reefs. Therefore, based on ocean observation data and the outputs of the Earth System Models from the Coupled Model Intercomparison Project Phase 6 (CMIP6), this paper uses Mahalanobis distance (MD) to evaluate the changes in sea surface temperature (SST), surface seawater pH, and surface dissolved oxygen (DO) content in the Indo-Pacific region in the future (2051−2080) and their potential impacts on warm water coral reefs under different Shared Socioeconomic Pathways (SSP1-2.6, SSP2-4.5, and SSP5-8.5, referred to as SSPs), relative to the historical climatology (1971−2000). Results show that: (1) the model outputs can well reproduce the spatial distribution characteristics of the historical ocean climatology, and the multi-model ensemble mean can significantly reduce the errors of individual model simulations; (2) the future ocean climatology of Indo-Pacific will change dramatically under different climate projection scenarios, including an increase in SST, a decrease in pH and DO, and the changes will intensify with the increase of greenhouse gas emission concentrations; (3) there will be significant changes in the marine climate of the Indo-Pacific, with the emergence of climate novelty. Substantial climate shift is projected to occur in the tropical eastern Indian Ocean, tropical western Pacific, northern Pacific, and mid-high latitude regions in the Southern Ocean, with approximately 15.23% (SSP1-2.6), 86.12% (SSP2-4.5), and 99.89% (SSP5-8.5) of the Indo-Pacific region experiencing a moderate degree of climate novelty (MD＞8), while around 89.04% (SSP5-8.5) of the Indo-Pacific region will reach an extreme degree of climate novelty (MD＞12); (4) From 1970 to 2080, the densely distributed areas of coral reefs in the Indo-Pacific will experience an increase in temperature of approximately 1.89-2.17 ℃, a decrease in pH of 0.21-0.22, and a decrease in DO content of 0.006-0.007 mol/m³, and the changes in the Red Sea and Persian Gulf are particularly prominent.