The first systematic study of the (IrnN)0,± (n=1~6) clusters was herein presented by using the B3LYP method of density functional theory (DFT) with the LANL2DZ for Ir atoms and the 6-311+G (3df) for N atoms. The result showed that the ground state configurations of the (IrnN)0, ± (n=4~6) clusters were all three-dimensional. There were much more absorption peaks in the Raman spectrums of Ir3N, (Ir4N)0,+ and (Ir6N)0,± clusters than other clusters. There was no absorption peak only just in the IR and Raman spectrums of the (Ir4N)- cluster in the small frequencies. The outcome is very useful to validate the predicted trend of structural transitions experimentally.