Abstract: The purposes of this study are to explore the impact of the rapid development of rice-crayfish integrated on the utilization of cropland, and how to balance the development of rice-crayfish fields with the food and ecological security. The results show that: (1) The change process of the spatio-temporal pattern of cropland has been expanding westward to Guanghua town and southwest to Yangshi town with the center of the Yuanlin town in the past 20 years. Cropland was converted into newly added construction land for 28.64 km2 and about 18.59 km2 water body; (2) The fragmentation of cropland is mainly caused by the expansion of construction land occupation of cropland in urban development, and the special planting characteristics of rice-crayfish fields rapid development; (3) Rice-crayfish fields are mainly converted from paddy fields. A part of dry land and water are also converted into rice-crayfish fields. The continuous expansion of rice-crayfish fields, especially the conversion of dry land and water to rice-crayfish fields, has brought about a certain degree of fragmentation of cropland. In conclusion, reducing farmland fragmentation is not the only development direction of agricultural production, especially under the factors of serious fragmentation of cropland, serious lack of rural agricultural power, low income of farmers and weak enthusiasm for farming in South China, rice-crayfish fields planting mode has a good potential and space in the agricultural development of South China.