An integrated wellhead device for filtering injected and produced gases is provided. The wellhead device comprises a horizontal tank body that is internally provided with an injected gas filtering system and a produced gas filtering system. The injected gas filtering system is internally provided with an oxygen removal chamber. A gas inlet of the injected gas filtering system is connected with an injected high-pressure gas source, and a gas outlet of the injected gas filtering system is connected with a gas injection well casing of Christmas tree. The produced gas filtering system is internally equipped with an oxygen removal chamber, a sulfur removal chamber and a carbon dioxide removal chamber. A gas inlet of the produced gas filtering system is connected with a gas production tubing of the Christmas tree, and a gas outlet of the produced gas filtering system is connected with a produced gas transmission pipe.