Low-dimensional CuI nanomaterials were synthesized in microemulsions containing cyclohexane, Triton X-100, n-pentanol and aqueous solution. The redox reaction took place in this system and the final products CuI were obtained. It's found that the morphology of CuI could be influenced a great deal by the experimental parameters such as w(0) (the molar ratio of water to surfactant), reactant concentration and the aging time. Hexagonal or shuttle-like CuI flakes, nanoparticles and nanofibers could be prepared respectively under certain conditions.