Old industrial areas first appeared in Britain and some other Western developed countries more than a century ago. In China, because of some problems existing in the industrial structure and the dominant industry, several provinces that had been prosperous now are declining. In those provinces, the speed of the economic development is slowing down, and many social problems are getting more and more serious. In fact, those regions have become old industrial areas. In this paper, considering the foreign researches on old industrial areas and the realities of China, the authors put forward four characters of the old industrial areas of China. They are as follows: uncoordinated in industrial structure, the dominant industries are at the end of the regional life cycle, the regions had been prosperous for a long time but now are declining, the living standard of the people is low and the social problems are serious. Considering the data's acquirability, the authors put forward four criterions and twelve indexes which are used to plot out the old industrial areas of China, and set up a suit of estimation system correspondingly. Based on those criterions, indexes and estimation system, the authors make an analysis of China in the unit of province. In the end, the provinces of China are classified into five elementary types: old industrial areas, quasi-old industrial areas, industrializing areas, regular development areas and rapid development areas. Heilongjiang, Shanxi, Liaoning and Jilin are presently the old industrial areas of China in this paper.