Abstract: Huang-Huai-Hai Plain is one of the most crucial grain-producing regions in China. Agricultural spatial patterns can serve as the prominent decision-making on the "agriculture, rural areas, and farmers" challenges during urbanization. The significant theoretical and practical value can also hold to promote the high-quality regional agriculture in the new era. Furthermore, the agricultural space can be defined as the critical component of the "Three Zones and Three Lines" system in territorial spatial planning, particularly for "a functional space primarily dedicated to agricultural production and rural livelihood". Together with the urban and ecological space, the fundamental structure can be constituted for the territorial protection and utilization at regional scale. Taking 342 administrative villages in Quzhou County of the Huang-Huai-Hai Plain as research units, this study proposed the concept of the agricultural space from the "material-function" perspective. An evaluation index was also established for the agricultural spatial quality using these two spatial attributes. Spearman's rank correlation coefficient and coordinated development degree were employed to measure the agricultural spatial quality from 2011 to 2021. A systematic analysis was made on their interconnections among the internal elements. The results show: (1) Agricultural spatial quality demonstrated a significant upward trend. The spatial pattern was formed as a more balanced structure with "Quzhou Town as the core hub and surrounding township centers as secondary nodes". The quality of the agricultural material space was improved slightly towards the balanced spatial development. Farmland quality showed the minor decline, while the village quality significantly increased, indicating the trade-off complementary. Agricultural functional space quality generally rose with a "high northwest-low southeast" spatial pattern. Main growth poles were emerged in the northern/eastern villages of the Quzhou and southern Henantuan Town. (2) Spearman correlation indicates that there was the trade-off and synergistic relationships among elements. Synergistic relationships existed among the farmland quality, production and ecological function. Living functions were synergized with the village quality. Trade-off relationships also occurred between any elements from material and functional space. There was the strong synergistic relationship among farmland quality, production, and ecological functions. While there were the intensified trade-off relationships between village quality and farmland quality/production functions. (3) Overall coordination of the agricultural spatial quality was improved significantly. Yet there was the more pronounced regional imbalance between urban and rural areas. There was the slight increase in the coordinated development degree between agricultural material and functional spaces. High-coordination areas were expanded significantly, while the low-coordination areas mostly appeared in the centers of the township. The overall coordinated level of the agricultural space was improved markedly, with the stable hot/cold spot distributions. However, there was the intensified imbalance between material and functional spaces in the urban core areas. As such, the targeted analysis was conducted to define the concepts of the agricultural space and its quality in the context of the high-quality development. Among them, the agricultural space was also divided into the agricultural material and functional space from the material-entity and virtual-functional dimension. The conceptual connotation of the agricultural space was enriched for the agricultural spatial studies at sub-county scales. Thereby, the finding can also provide a strong reference to advance the high-quality agricultural space in the Huang-Huai-Hai Plain region of China.