The effect of pyrolysis conditions on char reactivity was studied in this paper. The char samples were prepared in a N-2 atmosphere from the vitrinite constituents of two bituminous coals (YX and JJ) and their demineralized samples at different temperatures (800-1200 degrees C) and for different residence times. The effect of pyrolysis intensity on the carbon microstructure in the resulting char was characterized by the X-ray diffraction (XRD) technique. The reactivity of the char samples prepared under different pyrolysis conditions was measured by isothermal thermogravimetric analysis methods in an air atmosphere. The results show that the reactivity of the coal char decreases with increasing pyrolysis intensity and, when the pyrolysis temperature is high enough, the reactivity of the chars prepared from two coals and their demineralized samples tend to be the same. With increasing pyrolysis intensity, the growth of the carbon microstructure, accompanied by diminishing catalytic capability of minerals, results in the decrease in char reactivity.