The Changsha–Zhuzhou–Xiangtan region has experienced rapid social and economic development over the past 40 years, and cultivated land has changed dramatically. The contradiction between built and cultivated land has intensified, for which the local government has implemented a series of policies related to cultivated land protection. However, thus far, it is not clear what the substantial effects of the cultivated land protection policies are. To this end, this paper quantitatively characterizes the changes in the Changsha–Zhuzhou–Xiangtan region during the 20 years before and after the implementation of the cultivated land occupation balance policy, based on land use data from 1980, 2000, and 2020 using intensity analysis. In this paper, we examine the types of spatial land use patterns occurring in Changsha–Zhuzhou–Xiangtan since 1980 and explore the transition path of land use types in urban–rural integration. After the cultivated land protection policy, the transformation relationship between land use types and the changing trend of the cultivated land area was analyzed from the landscape scale. The influence of policy factors on the transformation of land use types was revealed. The results show that, from 1980 to 2020, the changing intensity of construction land and unused land was relatively large and was in an active state; the amount of built land in the Changsha–Zhuzhou–Xiangtan region has been growing, with a net increase of 1101 km2, while the amount of cultivated land has been showing a net decrease, with a net reduction of 677 km2. Moreover, the cultivated land has mainly been converted into built land, and the lost cultivated land area in Changsha–Zhuzhou–Xiangtan has not been fully compensated elsewhere in the region, indicating that the cultivated land protection policy has not been able to maintain the cultivated land area in Changsha–Zhuzhou–Xiangtan. From 2000 to 2020, cultivated land change was mainly due to exchange, which indicates that the policy has had a particular effect on the protection of cultivated land. Still, if the government wants to achieve the “balance of cultivated land occupation and compensation” goal, it must establish a complete system for the allocation of cultivated land resources. This study can provide a scientific reference for further implementing the cultivated land protection policy, which is thus of great significance for promoting the construction of the Changsha–Zhuzhou–Xiangtan region and its high-quality economic and social development.