Abstract: By means of program pyrolytic modeling,major parameters on the secondary hydrocarbon generation of coal have been described in detail,for instance,instantaneous hydrocarbon production,cumulating hydrocarbon production,cumulating amount of hydrocarbon generation,cumulating degradability and residual carbon.According to the original coalification degree of the daughter samples,the peak temperature of secondary pyrolysis changed in different styles such as lag,advance and fixation.To the coal at the metaphase pyrolytic stage,the reactive temperature zone of hydrocarbon generation extends to the lower temperature direction and the secondary hydrocarbon generation starts earlier due to the existence of weak chemical bond and bituminizied substance.To the coals at the early and terminal pyrolytic stage,activation of secondary hydrocarbon generation needs equivalent or stronger reactive conditions than the past since the hydrocarbon generation is mainly depend on the pyrolysis of principal part of the coal structure.The secondary hydrocarbon generating potential of coals is limited by primary evolution degree.Based on the stage characteristic of secondary hydrocarbon generation of coal and the self generating and self reser ving specialties of coalbed methane,the superimposed metamorphism beyond the period of hydrocarbon generating peak(Ro.m≌0.95%)offers the most effective ways to elaborate the hydrocarbon generating potential of coals.