The invention relates to a cleaning machine used for washing external wall of pipes, which pertains to the special equipment of industrial production and is suitable for cleaning the external wall of the petroleum chemical pipeline, removing scale, rust and the vitiated old anticorrosion coating, and spaying. The invention mainly consists of a frame, a driving wheel, protective strips, working parts, lateral wheels, sliders, a radial wheel wire rope, a wire rope driving wheel, a wire rope driven wheel, a driven wheel, a governor and counterweight. The working parts comprise a hydraulic water nozzle, an impactor, a wire brush, a polishing wheel and a paint gun. The invention is characterized in that the cleaning machine which is used for washing external wall of pipes can walk on the pipes and work continuously with high efficiency. A plurality of cleaning ways can be combined for use or a single cleaning way can be used. The invention has good washing effect.