In a method of managing process factors that influence electrical properties of printed circuit boards (PCBs), n process factors are arranged in an order according to different influence to one kind of electrical property of the PCBs. The different influence is determined by first experiments designed using the Taguchi method. M process factors that have important influence to the electrical property are obtained from the n process factors according to the order to design second experiments. A computing formula for the electrical property is fitted using the m process factors according to simulated results of the second experiments, and a variation range of each of the m process factors is computed according to the computing formula.