In this paper, a carbon based iridium (Ir) catalyst was prepared by an ion exchange procedure using H2IrC16 as precursor and a strong basic anion exchange resin as substrate. The Ir/Carbon sample was obtained by carbonizing the precursor. Effects of carbonization parameters such as temperature and time on size and dispersion of iridium crystallite were studied. Samples were prepared at 400 ℃ and 500 ℃ to investigate the effect of carbonization temperature. The SEM image of the Ir/Carbon composite shows a hard particle of 0. 2 - 0. 4 mm in diameter, which maintains a spherical shape. The TEM images of the catalyst show that no obvious effects of carbonization temperature or time are observed on the iridium particle size. Calcinated Ir nanoparticles prepared in ion exchange still keep their small particle-sized and narrow-sized distribution. The content of Ir supported on carbon can be well controlled simply by adjusting the relative ratio of Ir to carbon. Such a promising synthesis procedure is a versatile approach that can be extended to the fabrication of some carbon-supported metal catalysts or as a simple, rapid, and highly sensitive method.