The invention relates to a method and a device for joint denitrifying by denitrification and anaerobic ammonia oxidation embedding particles, and belongs to the field of sewage. The method comprises the following steps of respectively embedding a WPU (water-borne polyurethane) material by separated denitrification bacteria and anaerobic ammonia oxidation bacteria, putting the denitrification embedding particles into a flow-separated ball, putting anaerobic ammonia oxidation embedding particles into a Pall ring or into water in a floating state, and setting the denitrification embedding particles and the anaerobic ammonia oxidation embedding particles into an incomplete mixing state. The device comprises a water bath constant-temperature system, a sealing device, the flow-separated ball, the Pall ring and the like. The method and the device have the advantages that after embedding of the denitrification bacteria and anaerobic ammonia oxidation bacteria, the influence to the activity is avoided, the amounts of the denitrification bacteria and the anaerobic ammonia oxidation bacteria in the system are increased, the loss of bacteria amounts is reduced, the problems of slow growth of the anaerobic ammonia oxidation bacteria and stricter growth environment requirement in an anaerobic ammonia oxidation technology are solved, and the denitrifying efficiency of the system is improved by combining a nitrifying mode; the two types of embedding are set into the incomplete mixing state in the device, and respective feeding ratios can be flexibly adjusted according to the water quality.