In order to optically refocus three-dimensional (3-D) objects on their real depths, we design an adaptive periodic δ-function array (A-PDFA)-based 3-D optical refocusing method. An A-PDFA kernel with adaptively determined impulse number is first generated, and next by convolving this A-PDFA with the elemental image array (EIA) captured using an integral imaging system, the depth-filtered EIA is obtained to finally refocus the objects on their real depths. Based on simulations and experiments, the performance of the A-PDFA-based 3-D optical refocusing method is confirmed with the widest effective process zone and the highest image quality compared to other classical 3-D optical refocusing methods. Thus, it is believed the proposed method potentially can be used in various 3-D imaging and display applications.