Agricultural trade is the foundation of world trade and an important link in economic and trade relations between countries or regions. Exploring the competitiveness and complementarity of the agricultural trade between China and the Association of Southeast Asian Nations, or ASEAN, could provide a theoretical basis for tapping the growth potential of the agricultural trade between China and ASEAN and expanding the trade relationship. According to the theory of comparative advantage, trade complementarity theory, and intra-industry trade theory, and based on UN Comtrade data from 2013 to 2022, this study uses the Regional Revealed Comparative Advantage Index, the Trade Complementarity Index, and the Intra-Industry Trade Index to measure the competitiveness, complementarity, and intra-industry trade level of China–ASEAN agricultural trade, including HS01-24 commodities. The results show that the agricultural trade between China and ASEAN is both competitive and complementary. The competitiveness of China’s agricultural exports to ASEAN is greater than that of ASEAN’s agricultural exports to China, and the complementarity of the former is less than that of the latter. Both sides have their own comparative advantage products, and there is also a strong competitive relationship in some agricultural product fields. The bilateral agricultural trade is mainly intra-industry trade, and the level is relatively high, while some strongly competitive agricultural products urgently need to transform from inter-industry to intra-industry trade. China and ASEAN should participate in bilateral trade based on the comparative advantages of their own agricultural products; ASEAN should improve the quality of agricultural products to enhance international competitiveness; China should tap into the market demand for ASEAN agricultural products to enhance the complementarity of its agricultural exports to ASEAN; and the two sides should formulate different policies for different types of agricultural products.