Eight different three-parallel distributed activation energy model (DAEM) reaction model processes, which were used to describe the pyrolysis of eight lignocellulosic biomass samples very well, were analyzed by means of the Cai–Chen iterative linear integral isoconversional method. The activation energies obtained from the isoconversional method were independent of the heating rate, which indicated that the isoconversional analysis was valid for the pyrolysis of lignocellulosic biomass. The resulting effective activation energies of the pyrolysis of all lignocellulosic biomass samples showed strong dependence upon the extent of conversion: in the low range of conversion, the effective activation energies increase (about 190–210 kJ mol–1) with increasing the extent of conversion; in the medium range of conversion, the effective activation energies exhibit a practically constant value (about 210 kJ mol–1); and in the high range of conversion, the effective activation energies increase (about 210–290 kJ mol–1) with increasing the extent of conversion.