In order to improve the mechanical property and sealing property of graphite under the condition of high strength mechanical seal,porous graphite material was prepared from coal processing valueadded products (coal coke and asphalt),and then coalbased antimony graphite sealing material was prepared by highpressure antimony leaching.The mechanical properties,microstructure difference,element composition changes and friction and wear properties of graphite material before and after impregnation were compared,and the enhancement mechanism of graphite properties after impregnation was analyzed.The results show the mechanical strength and wear resistance of graphite material after highpressure antimony leaching are significantly improved,among which density is increased by 26.6%,compressive strength is increased by 114.3%,hardness is increased by 63.3%,porosity is decreased by 94%,absolute wear is decreased by 89.3%,and average friction coefficient is decreased by 46.4%.After antimony immersion at high pressure,the pores in the graphite material are filled with metallic antimony and are linked to form strips,which act as the skeleton during the friction and wear process,so the antiwear performance of the graphite material is improved.In the coalbased antimony graphite sealing materials,the fine mesh metal filling can reduce the abrasive wear of material,thus maintaining the stability of the lubrication film,so it can be used as a seal material under harsh conditions such as high temperature.