Abstract: The conventional two-dimensional ray-tracing technique is a classical method for analysis of antenna-radom systems. How-ever, in point of detail treatment for field distortions introduced by the radom using above technique, the accuracy is usually uncertain due to the inherent errors associated with the ray-tracing approximation of the antenna near field.A very effectivy approach based on sampling theorem using plane wave spectrum （PWS） method is given in this paper, the effects of airborne radome on antenna radiation pattern are analysed from many aspects. Besides the analysis of regul arapparent boresigh error. Stress is put on the calculations of radom cross-polarization fields and sidelobes （flash lobe） induced by the reflection on inner surface of radom. A number of useful curves of every variation is shown and the varying regulations with respect to antenna scanning angle are also discussed.