In particular, heatwaves may cause more severe impacts on public health and induce a relatively higher level of vulnerability in populations that live in urban areas. The Paris Agreement in December 2015 set a goal to hold global warming to well below 2 \({}^{\circ}\)C and pursues efforts to limit it to 1.5 \({}^{\circ}\)C above pre-industrial levels [8]. A special report was also published in 2018 from the Intergovernmental Panel on Climate Change (IPCC) for the comparison between global warming of 1.5 \({}^{\circ}\)C and 2 \({}^{\circ}\)C above pre-industrial levels, which provides a general point that \"keeping global warming below 1.5 \({}^{\circ}\)C rather than 2.0 \({}^{\circ}\)C will reduce the difficulty in adaptation and the world will suffer fewer negative impacts on intensity and frequency of extreme events\" [9]. However, the global 1.5 \({}^{\circ}\)C and 2.0 \({}^{\circ}\)C warming target is just an emblematic indicator globally, and the vulnerability to global warming may vary from region to region and exhibit notable spatial heterogeneity [3]. China is very sensitive and vulnerable to climate change considering its huge population and geographic location [10; 11; 12]. Therefore, efforts for the projection of heatwave over China in the 21 st century and the differentiation of risks between 1.5 \({}^{\circ}\)C and 2 \({}^{\circ}\)C global warming levels is very important for understanding global warming and also useful for elaborating any national climate mitigation policies [6]. The change trend for heatwaves under a warming climate scenario has received much attention in recent years both globally and in China [13; 14; 15; 16; 17]. In addition, there are also some works devoted to the investigation of the changes of heatwave and exposure at the 1.5 \({}^{\circ}\)C and 2 \({}^{\circ}\)C warming levels [8; 18; 19; 20; 21; 22]. Over China, there has been a general significant enhancement in heat waves frequency, intensity and the area suffering from such events has expanded remarkably since the 1990s [13; 23; 24; 25]. For the heatwave projection over China in the 21 st century or under different global warming targets, the previous works indicate that heatwaves are expected to become more frequent, more severe, and longer lasting in the future. In terms of the spatial pattern, although there is no conscious result due to the different heatwave definition, most of the studies show that western northwest China is projected to experience more large heatwave increase [7; 14; 26; 27]. However, except for a few studies based on regional climate model (RCM) [28; 29], most of the studies are based on the original CMIP5 simulation with relatively coarse resolution (e.g., 0.5-2\({}^{\circ}\)) and most of the previous works mainly use a special period such as 2070-2099 to reflect the change of heatwaves in the 21 st century. Moreover, special analyses of the heatwaves and risk over China for increasing of 0.5 \({}^{\circ}\)C from 1.5 \({}^{\circ}\)C to 2.0 \({}^{\circ}\)C are also rare. The coarse resolution obviously cannot account for the fine-scale heterogeneity of climate variability and describe the regional heterogeneity. The heterogeneities at scales of 10-50 km are more meaningful for decision makers who require detailed information on potential impacts on crop production, local residents, hydrology, species distribution, etc. Motivated by the need of accurate regional climate change over China, especially the change of heatwaves, this study uses the CMIP5 datasets with a spatial resolution of 0.25 \({}^{\circ}\) (\(\sim\)25 km \(\times\) 25 km) from NASA-NEX to analyze the change of heatwave over China under Representative Concentration Pathway (RCP) 4.5 and 8.5. In order to describe the potential impact of the heatwave in China, we also examined the population exposure in the 21 st century under the 1.5 \({}^{\circ}\)C and 2 \({}^{\circ}\)C warming levels combined with the high-resolution population density map under RCP4.5 and RCP8.5 scenarios.