Abstract: Rain attenuation can severely affect the performance of the 5th generation (5G)mobile communication millimeter wave systems. By using the existing rain attenuation prediction models, we observed an anomalous phenomenon that when the link is shorter than 1 km, the adjustment factor is bigger than 1, which means that the predicted rain attenuation increases in spite of the path length shortened. By analysing the measured rain attenuation data supplied by ITU-R, we found that the effect of wet antenna attenuation is comparable with that of the path rain attenuation, thus it must be considered in short links. A wet antenna attenuation model related to the rainfall rate is proposed, and parameters in different frequencies are given, which fit well with the measured data. The method also provide a novel thought for short-link rain attenuation modeling by taking wet antenna attenuation into account, which can solve the anomalous phenomenon mentioned above. Results of this research helps to enhance the reliability of the margin design of 5G millimeter wave systems.