Based on 2018–2023 data, this study employs the Export Similarity Index (ESI) and the Commodity Supply-Demand Matching Coefficient (CMCI) to perform a multidimensional assessment of agricultural trade complementarity between China and the five Central Asian countries. Findings show that the two sides’ export structures are significantly dissimilar, resulting in strong overall complementarity. Central Asia possesses a clear advantage in land-intensive specialty products (e.g., flaxseed, raisins), in contrast to China’s advantage in processed agricultural goods (e.g., vegetable products, aquatic products), establishing a “resource-processing” dual-track complementary relationship. Analysis at the country level reveals a gradient distribution in the degree of complementarity. The evaluation further identifies high trade potential across scale, structure, policy, and infrastructure dimensions, with specific high-growth sectors including natural honey and frozen fish. The paper thus supplies empirical evidence and policy recommendations for optimizing agricultural cooperation.