Carbon Fiber Reinforced Polymer (CFRP) has become a core material for the lightweight design of primary load-bearing components in next-generation aircraft, owing to its high specific strength and stiffness, corrosion resistance, and structural tailorability. However, due to the intrinsic anisotropic mechanical behavior and weak interlaminar strrength, CFRP components are prone to non-uniform deformation and stress distribution during assembly, resulting from accumulated manufacturing tolerances and assembly coordination requirements. In severe cases, this can lead to irreversible damage modes such as fiber/matrix interface debonding, interlaminar shear failure, and matrix microcrack propagation. Focusing on the need for stress control during the assembly of aircraft composite panels, this study comprehensively considers key process steps including clamping and positioning, gap compensation, and mechanical joining. It reviews the current state of research and application of related technologies domestically and internationally—from the optimization and online adjustment of positioning layouts, gap measurement and compensation, to process control in mechanical joining. Future development directions for stress control technology in composite panel assembly are proposed, providing a reference for low- or no-stress assembly of flexible composite components.