Abstract: An oxygen capsule preparation method includes the following steps: performing three-stage separation on deodorized cocoa butter; then mixing negative oxygen ions with deodorized cocoa butter liquid obtained after the three-stage separation; storing ionic oxygen in the deodorized cocoa butter liquid; and finally filling the deodorized cocoa butter liquid treated by the negative oxygen ions into a capsule shell to be prepared into the capsule, thereby obtaining the oxygen capsule. The oxygen capsule provided by the present disclosure is high in oxygen content, has a good oxygen supplementation effect, and has a good prevention or treatment or adjuvant treatment effect on various chronic non-infectious diseases (such as hypertension, gout, gastric ulcer and anxiety disorder), systemic lupus erythematosus and altitude stress.