Abstract: According to the design indexes and functional requirements of the movable solid wall test section for the 5.5 m × 4.0 m acoustic wind tunnel, this report presents the design project of overall scheme. The simulation calculation is carried out for the strength, stiffness and mode of the frame in the movable solid wall test section. The key technologies of positioning and locking, lifting mechanism, replaceable lower wall panel and adjustable opening side wall panel are studied in detail. At the same time, specific solutions are provided for the key problems in its processing and assembly process. The above research contents have important reference value for the design of the closed test section of the large acoustic wind tunnel of the same type.