In iris preprocessing,the located iris was divided into 8 layers at first,and each layer was normalized by different standards to unwrap the iris image into stepped shape,which avoided the data repeat or loss caused by traditional normalizing method. By using the frequency-selective character of 2D Gabor wavelet,the iris features were extracted and recognized respectively in different spatial frequency bands. In the end,by comparing the recognition results in different frequency bands,the spatial frequency characteristics of iris texture were obtained. The experiment shows that when the spatial frequency changes from 0.005 to 0.04,the recognizable iris features can be effectively extracted,and the recognition can be successfully realized. However,the extracted features will be full of noises and the iris will not be effectively recognized when the spatial frequency is lower than 0.005 or higher than 0.04.