An asteroid called Kaidun fell on December 3, 1980, in Yemen (15° 0′N, 48° 18′E). Investigations on this large-sized meteorite are ongoing today. In this paper, interactions between cosmic rays-earth atmosphere and cosmic rays-Kaidun meteorite were modeled using a cosmic ray generator FLUKA Monte Carlo code. Isotope distributions and produced particles were given after these interactions. Also, simulation results were compared for these two types of interactions.