The molecular dynamics method and quenching technique combined with the Gupta potential and the Sutton-Chen potential are used to study the melting properties of Irn （n=13, 14, 55, 56, 147 and 148） clusters. Our results show that the structures and melting behaviors of these clusters described by both potentials are generally in agreement with each other: the same ground state geometrical structure and the same trend of variation of the melting point and the pre-melting interval with cluster size are obtained for both potentials, and for the small Irn （n=13,14） clusters, the peak value of heat capacity is delayed from the saturation value of Lindemann index. While, for each of these iridium clusters, the melting point from the Gupta potential is higher than that from the Sutton-Chen potential, and we attribute the main reason to the higher energy gaps between the ground state and the first excited state of these iridium clusters from the Gupta potential than those from the Sutton-Chen potential.