After analyzing the image characteristics around the eye region and the states of eyeball when the eyes gaze something,an algorithm has been put forward to extract the eye feature and then locate its position on the image,and furthermore a method has been proposed to locate the iris characteristic line and the iris center.Considering that there are some variable conditions,such as,the head gesture,the distance from eyes to CCD camera,the opening degree of eyes,and subject with glasses or without glasses in practical application,some experiments have been done with the algorithm proposed in this paper,and the results show that this algorithm can commendably adapt to these variable cases,and the iris-tracking accuracy can get above 92%.