Coal, as one of the most important sources of energy around the world due to the intensity of its exploiting and utilization, causes increasingly serious ecological problems, especially air pollution. Large amounts of pollutants are emitted during coal combustion, with NO_x and SO₂ being the principal compositions. Therefore, desulfurization and denitrification are extremely urgent. Many technologies have been developed and applied. Our paper introduces mature and new flue gas denitration and desulfurization technologies along with their processing principles, industrial status, merits, and demerits. The combination of SNCR and SCR technology avoids their respective shortcomings and improves denitrification efficiency and economy. Based on the present situation, future trends are put forward. Synergetic, effective, and cheap desulfurization and denitration technologies will be our focus.