We propose a model of coupled local moments and itinerant electrons to describe the iron-based superconductors. Here the spin-density-wave (SDW) order of the itinerant electrons is not driven by Fermi surface nesting but is induced by the Hund's rule coupling with the local moments. The superconducting pairing is of the same origin whose strength can reach strong coupling. The existence of the local moments is supported by various anomalous magnetic properties which are in quantitative agreement with experiments.