The invention discloses a purification device and method for zirconium tetrachloride synthesis gas. The device comprises: a silicon storage device, which is used for storing silicon, wherein zirconiumtetrachloride synthesis gas obtained by preparation of zirconium tetrachloride in a chlorination process is introduced into the silicon storage device, the silicon in the silicon storage device reacts with the chlorine gas in the zirconium tetrachloride synthesis gas to generate silicon tetrachloride so as to remove chlorine gas from the zirconium tetrachloride synthesis gas, thus obtaining firstsynthesis gas; a first cooler, which is connected to the silicon storage device, and is used for cooling the first synthesis gas to precipitate solid zirconium tetrachloride, thus obtaining second synthesis gas; and a second cooler, which is connected to the first cooler and is used for cooling the second synthesis gas to precipitate liquid silicon tetrachloride, thus obtaining tail gas. The chemical reaction method is employed to remove chlorine gas from the synthesis gas, simplifies the separation process of zirconium tetrachloride synthesis gas, lowers the requirements of separation equipment, and reduces the separation cost, the silicon tetrachloride generated at the same time of chlorine gas removal can be further used for polycrystalline silicon production, and the chlorine elementcan be recycled.