The present invention relates to a method for preparing an oxygen carrier by using phosphogypsum, and applications of the carrier, and belongs to the technical field of solid waste resources. The method comprises: carrying out nature air-drying on phosphogypsum, adding bentonite to the phosphogypsum, completely and uniformly mixing, granulating, and drying to obtain phosphogypsum particles; introducing CH4 or CO gas to the obtained phosphogypsum particles, carrying out pre-reduction for 30-120 min at a temperature of 800-1100 DEG C to obtain a reduction product, and removing volatile impurities (heavy metals and organic compounds); carrying out oxidation regeneration on the obtained reduction product for 30-120 min at a temperature of 700-900 DEG C under introduction of 50-200 ml/min of anhydrous air atmosphere to obtain a regeneration product; and adding a carrier to the obtained regeneration product, completely and uniformly mixing an auxiliary agent and an active component to obtain a mixed product, carrying out molding processing on the mixed product according to the actual demand, and calcining for 6-12 at a temperature of 700-900 DEG C to obtain the oxygen carrier. A purpose of the present invention is to use the phosphogypsum as the oxygen carrier so as to achieve a lot of utilization of the waste resources.