In this study, the effect of structural characteristics of cellulose on its pyrolysis behavior was investigated. The structure of crystalline cellulose was altered by ball milling (BM) pretreatment, resulting in decreases in crystallinity and degree of polymerization. The initial pyrolysis temperature of BM-cellulose decreased, as well as the temperature at which maximum weight loss rate was achieved. Moreover, BM-cellulose was observed to produce more solid residue. The pyrolysis process was fitted by n-order reaction model. The global activation energy of Un-treated cellulose (228.3-270.6 kJ/mol) was higher than that of BM-cellulose (166.8-187.0 kJ/mol). TG-FTIR experiment showed that BM-cellulose yielded more CO2 and H2O than Un-treated cellulose. This research provided a comprehensive analysis of the effects of structural characteristics of cellulose on the pyrolysis behavior of cellulose.