CuI films can be prepared by the iodization of Cu metal films. In order to optimize the photoelectric properties of iodized CuI film, the CuI films were prepared with layer by layer iodization method, and then the CuI films were treated by post annealing and layer by layer annealing process. The structure, surface morphology and photoelectric properties of the samples by different annealing process were analyzed. The crystallinity of the CuI film is improved significantly after layer by layer annealing process. The surface density increases under the post annealing process, which can be ascribed to the movement of CuI grains along the two-dimensional plane. The transmittance of the CuI film increases to 80%~90% after post annealing process, and the resistivity of the CuI film is optimized to 0.034 Ω·cm after layer by layer annealing.