Abstract: Based on panel data of China's agricultural export trade with ASEAN countries from 2010 to 2023, the “3D” theoretical framework of New Economic Geography, and stochastic frontier gravity and trade inefficiency models, the study quantitatively analyzes the efficiency levels of China's agricultural export trade with ASEAN countries, explores key factors influencing this trade efficiency, and calculates the potential scale of bilateral trade and expandable trade space. The results show that China's per capita GDP, population size of ASEAN countries, and language similarity among ASEAN nations significantly positively promote China's agricultural exports, while bilateral geographical distance or shared borders have significant negative impacts on China's agricultural exports. Density factors of ASEAN countries, distance factors, and product tax rates significantly enhance China's agricultural export trade efficiency, whereas political stability in segmentation factors significantly inhibits such efficiency improvement. Overall, China maintains high agricultural trade efficiency with ASEAN countries, achieving balanced trade efficiency levels. Accordingly, policy recommendations are proposed from three aspects of increasing economic density, shortening economic distance, and reducing economic segmentation to enhance China's agricultural export trade efficiency with ASEAN countries.