Abstract: Abstract: At present, China implements an extensive agricultural space management mode based on quantity control. Although it has the necessity and feasibility in national level, the eastern developed areas have encountered great implementation resistance, resulting in the dilemma of dual low efficiency of quantity protection and production capacity. There is still a huge gap between the current management mode and practical demands of the eastern developed regions. Therefore, it is urgent to put forward the agricultural space optimization strategy for high-quality development. To this end, this study defined the basic concept of the agricultural space, and pointed out that agricultural space was a physical entity composed of most agricultural production space and a small amount of farmers' living space, and also an organic whole with certain structure and function formed by interrelated and interacting elements. Furthermore, this study concluded that agricultural space had three connotations: social foundation, human nature need and functional diversity. Through investigating current research of agricultural space optimization, the problems of current research were pointed out and they included: 1) insufficient coordination of agricultural space, meaning that ignoring other types of agricultural land other than arable land and ignoring the production factors flow, structure adjustment and function reflection; 2) insufficient understanding of demand transformation, meaning that healthy, green and experiential agricultural consumption had become a new trend; 3) insufficient attention to market mechanism, meaning that reliance on administrative means and lack of analysis of market patterns led to reduced production efficiency. Then, the basic principles of agricultural space optimization were put forward in order to meet the requirements of high quality development. Safety, including grain security, food security and ecology security was taken as the bottom line. Efficiency, mainly refers to the matching of demand and supply, was taken as the center. Quality, meaning the better agricultural products and service, was taken as the breakthrough. Based on these, the basic strategies of agricultural spatial layout optimization in the developed eastern coastal areas were proposed: the supply side coordinated agricultural space resources, including arable land, garden plots, farms and other types of agriculture space, the demand side analyzed agricultural demand changes, including diverse, customized and experienced needs. Then, supply and demand sides were connected through the market mechanism. According to the use of agricultural space, it was divided into the following three categories: 1) supporting agricultural space, with grain production as the main function; 2) promoting agricultural space, with non-grain agricultural products as main function, such as vegetables and fruits, meat, poultry and others; 3) integrating agricultural space, with agricultural leisure as the main function. For different type, different fine management measures were established and different optimization paths to meet the safety, efficiency, quality requirements were carried out. For example, in the supporting agricultural space, we should ensure grain supply and promote farming scale. In the promoting agricultural space, we should provide food diversity and facilitate agricultural clusters. In the integrating agricultural space, we should maintain ecological stability and facilitate agricultural specialization. In the eastern developed areas, the optimization of agricultural space layout must abandon the previous single perspective of quantitative protection. This study emphasized the overall value and comprehensive multifunction of agricultural space to serve the growing needs of urban and rural residents for better agriculture, which has a certain theoretical innovation significance and is expected to be tested and popularized in future practice.