Abstract: Scientifically assessing the level of high-quality agricultural and rural development is essential for local governments to understand regional development conditions, address development disparities, and accelerate China’s transformation into an agricultural powerhouse. Guided by the new development philosophy, this study integrates latent Dirichlet allocation (LDA) and grounded theory to analyze policy documents published between 2019 and 2025. Five axial categories, including innovation, coordination, green development, openness, and sharing, are identified, with coordinated advancement emerging as the core category. Based on these findings, an evaluation index system is developed. The entropy-weighted TOPSIS method, the Dagum Gini coefficient, and kernel density estimation are employed to evaluate the development levels of 30 provincial-level regions in China from 2011 to 2023 and to examine their dynamic evolution and spatial differentiation. The results indicate that the national average improved steadily, forming a pattern in which major grain-consuming areas maintained their leading position, grain production–marketing balance areas rapidly narrowed the gap, and major grain-producing areas improve steadily. Distinct differences are observed across development dimensions. Major grain-consuming areas demonstrate clear advantages in innovation and openness, while major grain-producing areas perform relatively well in coordination and green development. Grain production–marketing balance areas have achieved remarkable progress in innovation-driven development. The national distribution progressively shifts to the right, indicating an overall improvement in development levels. Major grain-consuming areas display substantial internal heterogeneity, disparities within major grain-producing areas continue to narrow. In contrast, grain production–marketing balance areas generally transition from relatively low to medium development levels, despite widening internal disparities in the later period. Overall spatial disparities show a converging trend. Interregional disparities remain the dominant source of overall inequality, while the contribution of intraregional disparities increases over time with some fluctuations. Based on these findings, this study proposes policy recommendations, including implementing gradient-differentiated development strategies, coordinating basic support with innovative breakthroughs, and deepening regional collaborative mechanisms.