NOVELTY - The method of treating sewage using a system, is claimed. The system comprises an artificial marsh tank, a water inlet pipe, an aeration device, a water outlet unit, and a microorganism plate. The microorganism plate is arranged in an upper portion of the artificial marsh tank. The tank includes a sandy soil layer, furfural slag layer, immobilized microorganism layer, a steel slag layer and a gravel layer. A water inlet pipe is connected with a water branch tube, and passes through a wall of the tank. A liquid valve and a liquid flow meter are connected with the water inlet tube.    USE - The method is useful for treating sewage using a treatment system (claimed).    ADVANTAGE - The method is capable of treating the sewage with improved processing efficiency.    DETAILED DESCRIPTION - The method of treating sewage using a system, is claimed. The system comprises an artificial marsh tank, a water inlet pipe, an aeration device, a water outlet unit, and a microorganism plate. The microorganism plate is arranged in an upper portion of the artificial marsh tank. The tank includes a sandy soil layer, a furfural slag layer, an immobilized microorganism layer, a steel slag layer and a gravel layer. A water inlet pipe is connected with a water branch tube, and passes through a wall of the tank. A liquid valve and a liquid flow meter are connected with the water inlet tube. An aeration device is connected with the tank through an aeration pipe and an aeration branch tube through the wall. A gas valve and a gas flow meter are connected with the aeration device. A water outlet unit is connected with the aeration device, and includes a water collecting groove. The water outlet unit is arranged on the artificial marsh tank opposite to the water inlet tube. The artificial marsh tank includes a steel-concrete structure, and an anti-seepage layer is arranged on an inner side of the tank body. A chemical medicine is mixed with sludge in the tank. The immobilization microorganism plate has a thickness of 4.5-6.5 cm, a length of 30-45 cm, and a width of 20-25 cm. The gravel layer has: gravel particle size of 2.8-3.4 cm 9 in a bottom portion; a particle size of 1-1.5 cm in an upper portion; and has a height of 30-35 cm. The steel slag layer has a steel slag grain diameter of 7-10 mm, and a height of 25-30 cm. The furfural slag layer has a particle diameter of 3-6 mm, and a height of 20-25 cm. The steel-concrete structure has a hole with a pore size of less than 3.