The development of 'Digital/Analog-Hybrid WINd tunnel (DAHWIN),' which is an innovative system integrating CFD (Computational Fluid Dynamics) with EFD (Experimental Fluid Dynamics), is presented. The objective to develop DAHWIN is to improve efficiency, accuracy, and reliability of aerodynamic characteristics evaluation in aerospace vehicle developments through mutual support between EFD and CFD. DAHWIN is constructed as a system seamlessly connecting two large facilities, 2m x 2m Transonic Wind Tunnel for EFD and a supercomputer system for CFD. The function of this system consists of optimization of test planning, an accurate correction of the wind tunnel wall and support interaction effects, quasi-simultaneous monitoring of EFD data in comparison with corresponding CFD data, the most probable aerodynamic characteristics estimation based on both EFD and CFD data, and so forth. Some early applications of DAHWIN to practical wind tunnel tests showed the usefulness of DAHWIN in terms of increasing efficiency and accuracy of both EFD and CFD.