NOVELTY - Synthesizing an ammonium bicarbonate fertilizer, comprises: filtering the dedusted and desulfurized carbon dioxide, pressurizing and allowing to enter into a main decarburization tower, introducing the rest carbon dioxide into the main tower into a fixed sub tower and then into an ammonia water tower, allowing ammonia water to enter the main tower and the sub tower, reacting with carbon dioxide, centrifugally processing to obtain ammonium acid carbonate and the rare ammonia water; introducing the exhaust gas into an ammonia recovering tower; and condensing the rare ammonia water.    USE - The method is useful for synthesizing an ammonium bicarbonate fertilizer.    ADVANTAGE - The method: reduces discharging quantity of greenhouse gas since the method processes the greenhouse gas; and allows recovering and re-utilizing the condensed ammonia water, and circulating and utilizing the dialysis water, and thus accomplishing the purpose of zero discharge.    DETAILED DESCRIPTION - Synthesizing an ammonium bicarbonate fertilizer, comprises: (i) filtering the dedusted and desulfurized carbon dioxide, pressurizing and then allowing to enter into a parallel connected main decarburization tower from the lower part of the main decarburization tower to the top, introducing the rest carbon dioxide into the main decarburization tower into a fixed sub tower for further reaction after being fully reacted with an ammonia water; (ii) introducing into an ammonia water tower after releasing the liquid ammonia to ammonia water by a releasing tower, allowing ammonia water to enter the main decarburization tower and the fixed sub tower by a pipeline from the upper part of each tower in the ammonia water tower, spraying from the top to the bottom, fully contacting and reacting with carbon dioxide gas entering from the bottom to the top to generate a carbon ammonium acid carbonate crystal, then collecting the ammonium acid carbonate crystal and the rest ammonia water in the main decarburization tower and the fixed sub tower, centrifugally processing to obtain ammonium acid carbonate and the rare ammonia water; (iii) introducing the exhaust gas generated by the fixed sub tower into an ammonia recovering tower for recovering ammonia gas, exhausting the rest tail gas to atmosphere, and collecting the rare ammonia water centrifugally processed by the ammonia recovering tower in step (ii) in a water pool; and (iv) condensing the rare ammonia water in the water pool by a reverse osmosis system to obtain the condensed ammonia water, introducing the condensed ammonia water into the main decarburization tower and the fixed sub tower for re-circulation and re-utilization.