Abstract: Aqueous zinc-ion batteries (AZIBs), using zinc metal as the negative electrode and aqueous electrolyte as the medium, possess advantages such as high safety, low cost, and environmental friendliness. However, their practical application is still constrained by problems such as zinc dendrite puncture, interfacial side reactions, and uneven ion transport. The separator, as a key component connecting the positive and negative electrodes and regulating ion migration and the interfacial microenvironment, has a decisive influence on battery performance due to its structure and function. Traditional glass fiber separators have significant shortcomings in mechanical strength, ion selectivity, and interfacial regulation capabilities, making it difficult to meet the development requirements of high-performance AZIBs. In recent years, constructing functionalized composite separators through multi-component, multi-scale composite modification has become an important approach to improve the overall performance of separators. This paper focuses on the structural engineering and interfacial regulation strategies of AZIBs composite separators, systematically reviewing the research progress of polymer-based, biomass-derived, metal/covalent organic framework functionalized, and multifunctional integrated composite separators. It summarizes their mechanisms of action in constructing directional ion channels, increasing Zn2+ migration numbers, enhancing puncture resistance mechanical support, and inhibiting hydrogen evolution and byproduct deposition. Finally, future development directions are proposed from aspects such as thickness/pore refinement, durability and stability, large-scale preparation and cost control, which are expected to provide a reference for the design and application of high-performance AZIBs membranes.