## 1 Introduction
Existing research has focused on the historical evolution and spatial patterns of population migration [27; 28; 29], the factors influencing migration and its driving mechanisms [30; 31], socio-economic impacts, and resource-environmental effects [32; 33; 34]. Additionally, studies have reviewed the evolution of China's hukou system reform and population migration policies [23; 35]. As aging intensifies, an increasing number of studies have begun to focus on the migration of the elderly population to actively address population aging [31; 36; 37; 38]. Overall, guided by classical population migration theories, these studies have explored the spatial and temporal characteristics of population migration and its influencing factors at both macro- and meso-levels, revealed the impact of socio-economic transformations on population migration and proposed countermeasures, and analyzed the role of families and family members as decision-makers in migration at the micro-level. While migration in China has been widely studied, rural migration remains a critical yet underexplored dimension, particularly in the context of the hukou system and urban-rural disparities. Occupying the lion's share of population movement [39], rural migration, in the context of the urban-rural dual system, profoundly reflects the urban-ruralgap and interaction resulting from the hukou system. It not only promotes cross-regional resource flows and regional system changes but also provides a key perspective for understanding China's unique social structure. The study of rural migration in China holds unique and significant research importance as it further highlights the complexity of urban-rural interactions and the far-reaching impacts of the institutional context on the basis of traditional population migration studies that do not differentiate between household categorizations. Existing research on rural migration can be categorized into four areas: (1) the interaction between rural migration and rural areas, focusing on challenges to village governance, rural poverty, rural pensions, and impacts on the land system and economic development [40; 41; 42]; (2) the interaction between rural migration and urban areas, examining issues such as social integration, pressure on public services, and social stratification [43; 44; 45]; (3) people-centered rural migrants, encompassing topics such as demographic characteristics and well-being security [46; 47]; and (4) rural migration activities. Relevant studies have primarily relied on sample surveys and questionnaires [48; 49] and have usually adopted theories such as push and pull factors and proximity effects to analyze the scale, patterns, and determinants of rural migration in specific regions. However, these studies are often limited by their reliance on rural-level data, which constrains their ability to capture broader spatio-temporal patterns and regional variations, thereby limiting the understanding of the macro dynamics of rural migration. The innovation of this study lies in its dual focus: it not only addresses the long-neglected issue of rural migration in China but also provides a macro-level analysis of its spatio-temporal patterns and network characteristics. Utilizing national census data from 2000, 2010, and 2020, this study explores the dynamics of interprovincial rural migration over the past two decades, filling a critical gap in the literature. Unlike existing studies that rely on limited sample surveys, this research leverages comprehensive national data to reveal the scale, patterns, and driving mechanisms of rural migration. Furthermore, by employing panel models to diagnose influencing factors, this study offers valuable insights for policymakers seeking to promote balanced regional development and sustainable urbanization, thereby supporting the implementation of new-type urbanization and rural revitalization strategies.