Abstract: Resolving the conflict between rural settlements and cultivated land is one of the critical steps in the plain agricultural areas. The “1.8 billion mu cultivated land red line” can also be implemented to prevent the “non-agriculturalization of cultivated land”. Therefore, it is crucial to explore the fundamental patterns of the spatial evolution on the rural settlements in the plain agricultural regions. This study aims to investigate the long-term evolution of the rural settlement spatial patterns in Liaocheng, Shandong Province, China. The North China Plain was characterized by the fertile land, dense agricultural use, and relatively low urbanization levels. The high-resolution satellite images were captured from 1982, 2002, and 2022. Rural settlement patches were interpreted and vectorized with the consistent geometric accuracy. GIS spatial analysis was carried out to determine the cumulative distribution metrics, such as the size, distribution, and clustering features of the settlements over 40 years. A novel framework of 14 compound spatial patterns was proposed to consider the full temporal trajectory across three time-nodes (T1-T2-T3), rather than each interval in the isolation as in the previous studies (T1: 1982-2002, T2: 2002-2022, and T3: 1982-2022). The results showed that: (1) Rural settlements exhibited a trend of increasing in size while decreaing in number, with the characteristic that growth in scale from 2002 to2022 was less intense than that from 1982 to 2002. Specifically, the total number of the rural settlements declined from 7742 in 1982 to 5119 in 2022. While the cumulative settlement area was more than doubled—from 54656.14 to 111986.21 hm². Most settlements remained at small scale. The average size followed a power-law distribution pattern, with a small number of the large settlements and a high proportion of small ones. Larger settlements were tended to be more dispersed (e.g., Average Nearest Neighbor ratio above 0.8). While the smaller settlements exhibited increasingly clustered into the spatial distributions (ANN values ranging from 0.6 to 0.7), indicating the stronger local aggregation. (2) The spatial patterns showed the diversified evolution patterns: The Independent-Independent and Merged-Independent patterns were dominant, together accounting for over 80% of the total number and settlement area. The most settlements maintained the structural and spatial stability over the 40-year period, especially in the agriculturally dominated areas with the limited urban influence. The long-term persistence of these patterns reflected the strict land-use constraints and the interwoven layout of the settlements and arable land in the plain agricultural region. The total area was depended mainly on the Independent-Merged, Independent-Urban Annexation, Merged-Merged, and Merged-Urban Annexation pattern. This variation was often driven by the rural land consolidation and urban expansion pressures. In contrast, there were the relatively limited effects of the New Establishment and Disappearance patterns. (3) Distinct spatial features were characterized by the different patterns: Independent-Independent and Merged-Independent patterns were aligned with the interspersed distribution of the settlements and farmland in plains. While the patterns near central urban areas shared the high risks of the urban encroachment, due to the radiation effects. Patterns surrounding central urban areas were strongly influenced by the urban expansion. The higher likelihood was found to be absorbed into urban space. The linear corridor distribution, such as those involving Merged or Disappearance, were predominantly aligned along the key transportation routes and inter-county development axes. The accessibility and coordinated urban-rural planning were significantly improved the spatial restructure of the settlements.