In this article, the author tries to analyze the process of agricultural growth after socialism and recent changes in the agricultural structure of Hainan Island which is situated in the subtropical zone of China from the viewpoint of the farming system, in an attempt to clarify intraregional differences of agricultural landuse on which no previous reports have appeared. The results are summarized as follows: 1) Hainan Island experienced rapid growth of agriculture after 1950, under the socialist system. The characteristics of this growth are expansion of arable land and establishment of estate-farms, which are a new type of agricultural organization different from the privatized farm (Old People's Commune), under capital support of the central government. At the same time, the landuse of the whole area also changed remarkably. That is to say, natural rubber, sugarcane and other tropical tree crops increased rapidly while traditional food crops, such as paddy and sweet potato, decreased. Especially, rubber increased to become the most important crop not only in landuse but also in the agricultural economy. 2) The agriculture of Hainan can be divided into eight regional types in terms of the farming system. Among these, monoculture of rubber cultivation is the most productive one occupied by estate-farms. In contrast, pure rice-growing, rice with sugarcane, rice with rubber, mixed farming, and horticulture are distinguished in privatized farms and their management scale is small. The gap existing between these two different organizations is very remarkable because of the irrational price policy. For example, the price of rubber per ton is three times as much as world market. That is why the estate-farm can develop so rapidly that Hainan has become the most important rubber cultivation area in China, even if it is marginal land in contrast with Southeast Asia. 3) In three case study areas, one of which is an estate-farm and two are privatized villages of Han and Loe people, we can find the rapid changes in landuse and farmers' management after the so-called new policy “Responsibility and Contract System” carried out in the early 1980's. In the case of the estate-farm which developed as a chief rubber producing district after 1957, not only agriculture but also the processing industry play an important role in farm management. Within this estate-farm, more than half the farmers are engaged in tapping of rubber by contract. On the other hand, both of the privatized villages showed that largely a diversified farming-oriented market economy has developed instead of the specialized farming as before, dominated by the main self-sufficient food crops. Especially, in the Loe people's village, slash and burn cultivation, which was the most important farming system until the 1950's, decreased very fast, because fields suitable for burning are cultivated by newer plantations of long-term tree crops, such as natural rubber and crude drugs. However, the difference of management scale among farmers is quite remarkable in each study area. This phenomenon is worthy of notice in connection with arising regionalization as an important factor. © 1990, The Human Geographical Society of Japan. All rights reserved.