Abstract: Polymetallic nodule is a kind of potential mineral resources. In order to explore such potential resources, many countries have made a great effort investigating and studying. The paper mainly introduces the distribution, composition, structure, texture, growing environment and growing model of the polymetallic nodules as well as the new conception and method in the study of this field. Based on the study results of marine geologists, it also points out the problem in the field and the research direction in the future.