It is important for civil aircraft design to research the icing influence. One of the main ways is adopting the icing wind tunnel test, which are extensively used for airplane research in USA and Europe. Many parameters were controlled during the icing wind tunnel,which cloud parameter was controlled with large difficulty and was measured indirectly, so the error was considerable which led to large difference from icing wind tunnel to another.Icing wind tunnel parameter calibration test in CIRA-IWT was introduced, and the cloud parameter correction methods were illuminated, which can provide reference to the icing wind tunnel research for civil aircraft.