Abstract: Gasification reactivity of nine coal chars of different rank were determined in CO_2 with a high Pressure thermoblance. The total pore volume, pore volume distribution and pore surface area of a lignite and an antfhracite with their respective chars were investigated, The total pore volume and pore surface area of the lignite char are higher than those of the anthracite char and consequently the reactivity of the former is higher.The reactivity of the demineralized anthracite char is five times higher than that of the char from original sample, and it may be presumed that the change is caused by the change of pore structural characteristies.The variations of pore surface area and pore volume distribution of the lignite char during the course of gasification may account for the change of its reactivity.