De-icing potentials (i.e. easy desorption of ice) of superhydrophobic surfaces (SHSs) are of great importance to their practical engineering applications. Recently, icephobicity of SHSs have attracted increasingly attention, however, researches on ice desorption behaviors of these surfaces under open and natural freezing environments are rare, and the intrinsic influence mechanism is still unclear. In this work, we innovatively investigated the whole process including hanging rainwater, hanging ice, ice desorption of the curved steel pipe surfaces with different wettability and microstructure under simulated freezing rain using high-speed photography, and the real-time ice adhesion of these surfaces through strain sensor voltage. The results show that raindrops on hydrophilic steel gradually spread out to become annular water film and further freeze to become long ring-like icicles, in contrast, most spherical raindrops easily roll down from the surperhydrohobic coating and just form unconnected point or surface-contact icicles. The desorption moment of point-contact icicles on the surperhydrohobic coating is 393 s earlier than ring-like icicles on bare steel under natural rain, and more than 210 s earlier under wind and vibration interference during the melting process. The real-time ice adhesive strength of the surperhydrohobic coating is significantly smaller than hydrophilic steel. Furthermore, the easy desorption mechanism of ice on curved hydrophobic/superhydrophobic coatings compared with bare steel under simulated freezing rain was analyzed from water sliding, rolling and spreading behaviors as well as ice adhesion. The key finding is that water film is an important factor for the de-icing performance of surfaces in practical freezing environment. Water-repellent surfaces can effectively improve ice desorption capacity in practical freezing environments by inhibiting formation of connected water film. This work will provide a new perspective for promoting anti-icing application of water-repellent surfaces in various engineering fields.