The developing of artificial neural networks is based On the research of modern neural science. Artificial neural networks reflect the basic feature of human brain's function，but it is not a real description of human neural networks，it is just some abstract，simulation and simplification of human neural networks. The fundamental goal to study this technique is to explore the mechanism of which human brain processes，memorizes and searches information，and the possibi1ity of using the principle to artificial intelligence. This paper introduces some neural networks' models and their applications.