Inlet cowl is an important part of aero-engine. Its anti-icing ability relates to engine performance, and even affects flight safety. In order to investigate anti-icing properties of aero-engine inlet cowl, influence of hot-air flow, entrance temperature, entrance velocity on icing condition of inlet cowl was obtained by icing experiment and anti-icing experiment in the icing tunnel. The test results show that the anti-icing capability of the inlet cowl is enhanced from the cone to the end of cowl. The anti-icing effectiveness of the inlet cowl increases with hot-air flow. The inlet cowl's surface ice type varies with entrance temperature and entrance velocity. The icing area of the inlet cowl increases with increasing entrance velocity. The research results have important guidance for the anti-icing system design and verification of aero-engine inlet cowl.