Seven different distributed activation energy model (DAEM) processes, which were used to describe the pyrolysis kinetics of wood, algae, lignin, corn stalk skin, kerogen, cellulose, and coal, were analyzed by means of the Friedman differential isoconversional method. It has been shown that the activation energies obtained from the Friedman method are independent of the heating rate. For all DAEM processes considered, the effect activation energies evaluated by the Friedman isoconversional method showed significant dependence on the conversion. The kinetic parameters obtained by means of the Friedman isoconversional method were used to reconstruct the conversions and rates data. The agreement between the reconstructed data and the data calculated by the DAEM is excellent at the presimulated and extrapolated conditions for all the DAEM processes. This indicates the DAEM process can be taken as an example to check the accuracy of some integral isoconversional methods in the determination of the activation energy.