An exemplary method of determining a pointing object position for three-dimensional interactive system, adapted for an interaction between a pointing object and a three-dimensional interaction display with embedded optical sensors. The method includes the steps of: acquiring a two-dimensional detected light intensity distribution caused by the pointing object acting on the three-dimensional interaction display; obtaining two light-shading intensity maximum values according to the two-dimensional detected light intensity distribution; and determining a one-dimensional positional information of the pointing object on a distance direction of the pointing object relative to the three-dimensional interaction display by use of the positional distance between the two light-shading intensity maximum values.