Abstract: A location algorithm based on integro-differential operators was presented for solving the difficulty of precise segmentation in NICE:II. The R layer of RGB iris image is chosen first, and the Gabor filter and gradient information are used to detect the reflection area. Moreover, Adaboost algorithm is used to detect iris area in the whole image, then the upper and lower eyelids are detected. A center template based on integro-differential operators was adopted to search the outer boundary of iris through iteration step by step, and cluster analysis was used to remove the noise on iris boundaries. Because the inner boundary of iris is weak, the homomorphic filtering is adopted to enhance the iris area, then the inner boundary is located. The proposed algorithm was tested under NICE:II, and the accuracy of the new method is 98.22%.