Abstract: In order to investigate the geochemical behavior of mercury in two bituminous coal at different combustion temperature, 4 samples of bituminous coal were collected from 4 typical coal mines in Huainan and Huaibei regions. The samples of coal ash at 400 ℃, 500 ℃, 600 ℃, 700 ℃, 800 ℃ and 900 ℃ were obtained by a quartz tube furnace. The content of Hg element in coal and coal ash samples were determined using ICP-MS, combined with X ray diffraction （ＸＲD） and Fourier transform infrared spectroscopy （ＦＴＩＲ） analysis. The results obtained are as follows: the abundance of Hg in bituminous coal is about 0.1 μg/g; Hg in bituminous coal is mainly in the form of residue, followed by exchangeable and carbonate binding states; volatile temperature of Hg in bituminous coal is at 400 ℃ to 500 ℃, a small amount of Hg is deposited in the slag; XRD experiments show that the variation of clay mineral content in bituminous coal is closely related to the variation of mercury; the presence of fixed carbon in the residue affects its Hg content; FTIR experiment shows that Hg content in bituminous coal has a good positive correlation with C=O functional group content, it indicates that the content of C=O in coal can be used as an indicator to detect the Hg content in coal.