Disclosed is a flue gas low-temperature adsorption denitration system and process. The system includes a booster fan, a cold energy recoverer, a flue gas cooling system, a flue gas switching valve, and two denitration adsorption towers. An inlet of the booster fan is in communication with an inlet flue gas pipeline. The booster fan, the cold energy recoverer, the flue gas cooling system, the flue gas switching valve, and the denitration adsorption towers are sequentially communicated. An outlet of the flue gas switching valve is in communication with each of the two second denitration adsorption towers. Flue gas outlets of the two denitration adsorption towers are in communication with a flue gas manifold. The flue gas manifold is communicated with the cold quantity recoverer. Two denitration adsorption towers take turns to carry out denitration and regeneration processes, so that continuous denitration operations of the system can be achieved.