Abstract: Civil aircraft should conduct icing airworthiness certification according to relevant icing airworthiness regulation requirements in order to obtain the type certificate, and icing wind tunnel test is the effective way to get the critical ice shape. Based on an engineering application of icing wind tunnel test for the Y12F aircraft, test techniques are summarized and analyzed, such as the test model design, simulation of the pneumatic de-icing system, test status transformation, test process, ice shape measurement and so on. A typical test result is represented in the end, which indicates that the pneumatic de-icing system could run effectively under the typical maximum icing condition, and ice could be removed during the work cycle of the system. There would be ice accretion during the interval of system running. Ice formed at the leading edge is always smooth, and the thickness of the ice is from 5 to 6mm. There is an obvious ice ridge about 3 to 4mm thick on the upper surface, and three ice ridges about 2 to 4mm thick accrete on the lower surface.