  The DArk Matter Particle Explorer (DAMPE) is a satellite-borne detector for
high-energy cosmic rays and $\gamma$-rays. To fully understand the detector
performance and obtain reliable physical results, extensive simulations of the
detector are necessary. The simulations are particularly important for the data
analysis of cosmic ray nuclei, which relies closely on the hadronic and nuclear
interactions of particles in the detector material. Widely adopted simulation
softwares include the GEANT4 and FLUKA, both of which have been implemented for
the DAMPE simulation tool. Here we describe the simulation tool of DAMPE and
compare the results of proton shower properties in the calorimeter from the two
simulation softwares. Such a comparison gives an estimate of the most
significant uncertainties of our proton spectral analysis.
