Pressurized oxy-fuel combustion has attracted much attention，which is considered to be a more efficient and cleaner second-generation oxy-fuel combustion technology. As the first step of coal combustion，different pyrolysis conditions (pressure,atmosphere，heating rate，etc.) directly affect the physical and chemical structure of char，which in turn leads to different combustion reactivity. At present，under the conditions of pressurized oxy-fuel combustion，there is few report on the correlation between the reactivity and structural properties of char. A pressurized concentrating photothermal apparatus whose maximum heating rate could reach 80 ℃/s was independently designed and established. Two kinds of Zhundong coals，Hongshaquan (HSQ) and Wucaiwan (WCW) were selected to prepare char under different pressures (atmospheric pressure -1.5 MPa) and pyrolysis atmospheres (N2，CO2). The specific surface area analyzer，Raman analyzer，thermogravimetric analyzer were used to systematically investigate the influence of pressure and pyrolysis atmosphere on the structural characteristics of char and its combustion reactivity. The results show that under inert N2 atmosphere，the char yield of HSQ and WCW coal at 1.5 MPa increase by 3.54% and 10.49%，respectively，compared with atmospheric pressure. While under CO2 atmosphere，compared with atmospheric pressure，the char yield of HSQ coal at 1.5 MPa decreases by 16.40%，and the char yield shows opposite trends with pressure changes under two kinds of atmospheres. Under N2 atmosphere，the specific surface area of HSQ/WCW char increases from 24.20/14.85 m/g to 26.27/46.19 m/g with the pressure increases from atmospheric pressure to 0.4 MPa. However，when the pressure continues to increase to 1.5 MPa，the specific surface area of HSQ/WCW char decreases from 26.27/46.19 m/g to 21.21/39.46 m/g. Under the same pressure，the pore structure of char prepared under CO2 atmosphere is more developed. At atmospheric pressure and 1.5 MPa，the specific surface area of HSQ char prepared under CO2 atmosphere is 6.46 and 9.03 times that of char prepared under N2 atmosphere，respectively. This is also the main reason why the combustion reactivity of HSQ char prepared under CO2 atmosphere is better than that prepared under N2 atmosphere. With the increase of pressure，whether it is prepared under N2 atmosphere or CO2 atmosphere，the ratio of I(GR+VL+VR)/ID calculated by the peak fitting calculation of the Raman spectra of two kinds of chars gradually decreases，and the chemical structure of the chars tends to be more stable，which also make the combustion reactivity of chars prepared under high pressure decreases. However，under the same pressure，the ratio of I(GR+VL+VR)/ID of HSQ char prepared under CO2 atmosphere is lower than that prepared under N2 atmosphere. Under high pressure，the gasification reaction of CO2 and char is enhanced，which consume more amorphous carbon，so the difference of I(GR+VL+VR)/ID is more obvious under two kinds of atmospheres. However，due to the dominant effect of the difference in physical pore structure，HSQ char prepared under CO2 atmosphere has better combustion reactivity. It could be concluded that the combustion reactivity of char is affected by physical structure and chemical structure.