The pupil center location plays an important role in the human-compu ter interaction gaze tracking system.An algorithm that combines radial symmetry with image selective threshold reversion is presented to locate the pupil center.Firstly,the eyes on a face image are extracted by the relative position of eyes and the center of the face area.The color eye image should be converted into a gray image,then the image is smoothed using the Gaussian smoothing to reduce the influence of noise.The gray scale image is reversed with a threshold,which can remove the influence of pixels′s gradient changes of the eye surroundings.After th image selective threshold reversion,we can use the radial symmetry to vote t he pupil center.In the experiments,we use the BioID and CASIA-IrisV4datasets t o test the approach,which demonstrates that the proposal can achieve higher accuracy in pupil center localization,the method meets the real-time requirement,so w e can apply it to the human-computer interaction gaze tracking system.