Abstract: Civil aircraft should conduct icing airworthiness certification according to relevant icing airworthiness regulation requirements, so understanding the airworthiness regulations requirements and formulating the effective conformity certification process are the key points of airworthiness certification. Based on an engineering application of icing wind tunnel test for the Y12F aircraft, relative airworthiness documents, latest aircraft icing research results, certification requests and techniques are summarized, such as setting of target test cases, confirmation of facility, transformation of test cases, test model designing and manufacturing, icing wind tunnel testing and so on. The formed airworthiness certification method conducts the certification of Y12F airplane de-icing system effectively, which is accepted by Civil Aviation Administration of China (CAAC) and Federal Aviation Administration (FAA) synchronously, and it lays a good foundation for getting the aircraft certification of CAAC and FAA.