The invention relates to an improvement method of needle coke used refined aromatic hydrocarbon oil. The improvement method of the needle coke used refined aromatic hydrocarbon oil comprises the following steps: taking oil rich in aromatic hydrocarbon, heating the oil to 400-490 DEG C by a heating furnace, introducing the oil into a polymerization tower, taking the material at the bottom of the polymerization tower and introducing the material into a flash tower, taking the flashed material at the bottom of the flash tower, cooling the material to the room temperature, introducing the material into a gas-liquid separator, controlling the vacuum degree in the gas-liquid separator to be 5-10kpa, taking the material at the bottom of the gas-liquid separator, and enabling the material to flow into a refined aromatic hydrocarbon oil buffering tank to prepare the raw material which is refined aromatic hydrocarbon oil for producing needle coke. The improvement method of the needle coke used refined aromatic hydrocarbon oil is simple in process; the oil rich in aromatic hydrocarbon with low content of aromatic hydrocarbon in domestic oil refining plant is processed, the content of the aromatic hydrocarbon is increased; the prepared refined aromatic hydrocarbon oil is applicable to production of the needle coke.