The invention discloses an acid modified Ce-Cu-Al-Ox composite mesoporous oxide adsorbent, a preparation method thereof, and application of the adsorbent in simultaneous removal of hydrogen sulfide and hydrogen phosphide. The preparation method comprises the following steps of using mesoporous aluminum oxide as a carrier, using metal oxide loading Ce and Cu as an active component, and further modifying by acid, so as to obtain the adsorbent. The preparation method has the advantages that the preparation method is simple, the operation is easy, and the cost is low; compared with the Ce-Cu-Al-Ox composite mesoporous oxide adsorbent not subjected to acid modification, the adsorbing effect of the adsorbent prepared by the method is obviously improved.