Abstract: The icing wind tunnel is the most important ground facility in the research of ice accretion tests and the ice anti/protection devices design of airplanes. With the increasing importance of the supercooled large droplets ice accretions on the airplane surface and the development of the SLD airworthiness, the SLD icing condition simulation capability need to be developed in the icing wind tunnel. This paper presents the analysis results of the SLD icing condition in CFR14-25 Appendix O and the requirements of the SLD condition simulation in the icing wind tunnel. The developing status and the key problems of SLD icing condition simulation capabilities in several icing wind tunnels, such as IRT and CIRA-IWT are also presented. The three main key problems in the development of the SLD icing condition capability in the icing wind tunnel are the generation of large water droplets and it's turbulent mixing characteristics with the cloud in wind tunnel, the supercool process of large drops and the drop spectra accurate measurement in wide bands. The development roadmap and the key technology solution method of SLD icing condition simulation capability of icing wind tunnel of CARDC are presented in the end of this paper.