Global climate change is anticipated to raise the overall temperatures and is likely to increase future mortality attributable to heat. China, a rapid developing nation with the world's largest population, has experienced noticeable changes in climate over the past century, with an annual increase in air temperature by 0.5-0.8°C. While increasing evidence is suggesting that climate change has posed significant health risks to Chinese population, including heat-related mortality, the extent to which climate change will affect future mortality and the sources of uncertainty in projecting prospective changes in mortality remain unexplored. Using GIS (Geographic Information System) and epidemiological approaches, this study estimates excess future premature deaths in large urban areas in China resulting from potential increases in temperature under climate change. Our projection includes 51 large Chinese cities in this study, which cover approximately one third of the total population in China. We use ArcGIS to combine temperature predictions from climate models, local temperature-mortality relationship and population forecasting and project the future excess mortality attributed to higher temperature during warm season. The study focuses on future temperature change during 2040-2050 relative to the baseline period 1950-2000 in the 51 cities selected. For future temperature projection, we ensemble outputs from 19 climate models used in the IPCC 5th Report, including outputs related to all four AR5 emission scenarios (RCPs 2.6, 4.5, 6.0 and 8.5). The results of this study inform decision makers of the direct health benefits of climate mitigation.