The invention discloses a method for efficiently cleaning and removing arsenic in copper-containing slag. The method comprises steps of crushing, fine grinding, oxygen pressure alkaline leaching, pH regulation, oxygen pressure acid leaching and the like. The method sequentially comprises the following steps: efficiently cleaning and separating arsenic in the copper-containing slag as well as lead, silver and other valuable metals, and recovering copper in the copper-containing slag. The method disclosed by the invention is low in energy consumption, less in environmental pollution and high in production efficiency. The reaction process of the method is simple and rapid, and the selectivity is high. The copper in the copper-containing slag can be efficiently leached, and the metals can be completely separated. Compared with the conventional copper-containing slag treatment process technology, the arsenic is removed in a sodium arsenate precipitation form through alkaline leaching before copper leaching, so that high-efficiency cleaning and arsenic removal can be achieved, the arsenic removal effect is excellent, and the arsenic content in the leaching solution is less than 1g/L. Moreover, the copper is recovered through the oxygen pressure acid leaching, and the finally prepared copper sulfate product has the copper leaching rate of more than or equal to 96%. The arsenic in the copper-containing slag is recovered in an arsenic slag form, and secondary pollution of the arsenic is avoided. The technology has the advantages of high metal recovery rate, low production cost, high-efficiency cleaning and the like.