"Industrial Reserve Army" is the product of modern industrial revolution, which widely exists in the industrial society. The huge "Industrial Reserve Army" can be either a huge source of productivity or the cause of serious unemployment. We may get the possibility from "Industrial Reserve Army" to "Industrial Forces", by identifying "Industrial Reserve Army" concept, analyzing the reasons of unemployment, and discussing the relations between Marx' theory of "Industrial Reserve Army" and the unemployment problems, which is supposed to provide theoretical references for contemporary Chinese labourers.