The invention discloses a method for producing kieselguhr by acid-leaching silicon slag with nickel laterite ores. A simple resource-based method is provided for solving problems existing in resource research of the silicon slag acid-leached by the nickel laterite ores, processes of grinding, acid leaching, drying and the like are preformed on the slag, the kieselguhr conforming to the national standard can be produced by the aid of low cost of the slag, and meanwhile, yield of nickel of a nickel smelting system is favorably increased. The method has the advantages of low invest capital and reliable product quality and belongs to cleaning process, and remarkable economic and social benefits are achieved.