This paper, on rural restructuring in China, focuses on the ability of agricultural heritage systems to adapt to modernizing conditions in the rural economy. Since 2002, when FAO initiated the protection of Globally Important Agricultural Heritage Systems (GIAHS), the value of agricultural heritage has been widely acknowledged, as has the importance and urgency to protect the systems in which they are embedded. However, such complex systems have not been fully assessed for their contribution to food security, ecosystem services and cultural preservation, as well as their ability to adapt to the demands of modernization. In fact, they have not been effectively evaluated as whole systems, largely because we have not yet devised satisfactory ways of studying complex systems, nor have we been able to assess them fully for their multi-faceted contributions to sustainability. This paper accepts the premise that such systems are sustainable in that they have survived as agro-ecosystems for many hundreds of years, having endured the predations of droughts, famines, plagues, floods and wars. This ability to sustain a rich diversity of biological and human systems is considered, in the theory of Complex Adaptive Systems (CAS), to be a form of resilience, meaning that these systems have either formed a new normal or returned to the old normal after a period of environmental or social stress. In effect, ancient agricultural heritage systems can be seen to represent what has been traditional and normal in China, but which today are faced with the overwhelming forces of modernization. Taking three examples from Qingtian County in Southern China, where physical and political conditions are consistent, the paper shows how similar rice-fish systems adapt differently and sustain themselves in the face of modernization, and particularly to the loss of youth and labor to urbanisation. One system self-adjusts by using remittances from abroad to sustain the system: an example of self-organization. In another township, the pursuit of tourism is the main form of adaptation to large losses of working population and marginal incomes. To maintain the landscape as a key attraction for tourists, this community has re-assembled abandoned rice terraces and is farming them as a collective enterprise under the auspices of a co-operative: an example of land and labor restructuring that has become common as the dominant form of agrarian change in China. In a third example, the local rice-fish system is being strengthened by modern farming technology and scientific techniques: an example of technological adaptation. The discussion explores the three responses as evidence of sustainable practice involving local restructuring, continued ingenuity, and the creative support of local governments in the face of the homogenizing demands of modernization.