Compared with monoculture, integrated aquaculture (IA) is a multi-species or multi-systems aquaculture model, and has the advantages of high resource utilization, environmental protection, diversified products, disease prevention and so on. Therefore, IA is generally regarded as a model of sustainable production systems of aquaculture. Structural optimization refers to the optimization of species composition and stocking quantities of each species within a specific IA system. This chapter will focus on the historical evolution, basic rationales, classification, structure optimization of the IA in China.