1. A sight tracking method, comprising: determining an observation region where an iris center of a to-be-tested iris image is located according to a target model; modifying a prediction region by using the observation region, to obtain a target region, the prediction region being a region where the iris center of the to-be-tested iris image is located determined by a kalman filtering method; and determining a position of fixation point of human eyes on a screen according to the target region.