The invention discloses a system and method for removing nitrogen oxides from the flue gas of a coal-fired power plant by internal circulation. The system is characterized in that the outlet of a coal-fired boiler is connected to the inlet of a flue gas mixer through a heat exchanger; the outlet of the flue gas mixer is connected with a flue gas inlet in one end of each of a plurality of hydrotalcite adsorption beds through a flue gas conveying pipeline; a flue gas outlet in the other end of each of the hydrotalcite adsorption beds is connected to a flue gas exhausting part; a heat dissipation air outlet of the heat exchanger is connected to air inlets of the hydrotalcite adsorption beds through a desorption pipeline; and the air inlets of the hydrotalcite adsorption beds are connected to the coal-fired boiler through a desorption reflux pipeline. According to the system and method for removing nitrogen oxides from the flue gas of the coal-fired power plant by internal circulation, the structure is simple and compact, the operability is high, steps such as preoxidation, adsorption, desorption and reduction of NOx are combined in an organic manner, NOx is limited in an internal circulation purification system during the treatment process, and the final removal and zero emission of NOx are truly realized; besides, a reducing agent is not needed, the denitration cost is greatly reduced, and a high popularization and application value is achieved.