The present invention relates to a method for concentrating and recovering noble metals from printed circuit boards of discarded mobile phones and catalysts of discarded cars using discarded nonferrous slag, which is industrial waste discharged from a process for refining nonferrous metals such as copper, lead, zinc and the like, and more specifically, to a method for concentrating and recovering gold, silver, platinum, palladium, rhodium and the like contained in printed circuit boards of discarded mobile phones and catalysts of discarded cars by melting discarded nonferrous slag, printed circuit boards of discarded mobile phones and catalysts of discarded cars at a high temperature through a single process to reduce and separate iron oxide contained in the discarded nonferrous slag and simultaneously melting and separating copper, iron, tin, and nickel contained in the printed circuit boards of discarded mobile phones to use the generated iron, copper, tin, and nickel alloy as a collector metal for noble metals. The method for concentrating and recovering noble metals from printed circuit boards of discarded mobile phones and catalysts of discarded cars using discarded nonferrous slag of the present invention comprises the steps of: mixing and melting discarded nonferrous slag and a solvent, which is a slag composition controller; inserting printed circuit boards of discarded mobile phones and catalysts of discarded cars to the obtained molten metal to melt the same; and maintaining the same for a predetermined amount of time to separate the same into a noble metal-collected alloy phase and a slag phase containing no noble metals. In addition, the present invention relates to a method for recovering valuable metals such as iron, copper, tin, nickel and the like in addition to noble metals such as gold, silver, platinum, palladium, and rhodium from printed circuit boards of discarded mobile phones and catalysts of discarded cars, and recycling the generated slag without environmental problems. According to the present invention, the amount of the generated alloy phase is increased without using a collector metal for noble metals such as copper, iron, lead, and nickel and carbon as a reducing agent which increase processing costs by using discarded nonferrous slag, which is industrial waste discharged from a process for refining nonferrous metals such as copper, lead, zinc, and the like, as a solvent, which is a slag composition controller, and a noble metal collector simultaneously, and using a plastic component contained in printed circuit boards of discarded mobile phones as a reducing agent, and thus an alloy phase and a slag phase can be readily separated, thereby simultaneously reducing processing time and minimizing the amount of a solvent such as alumina (Al2O3), quicklime (CaO), magnesia (MgO), iron oxide (FeO) and silica (SiO2). Accordingly, noble metals such as gold, silver, platinum, palladium, rhodium and the like can be concentrated and recovered through a single process by simultaneously treating different industrial waste such as printed circuit boards of discarded mobile phones and catalysts of discarded cars, and waste material can be recycled to be used as a material for the high-technology industry, and thus it is possible to maximize the coefficient of utilization of noble metal resources in resource-poor Korea, which depends on imports for all of noble metal resources.