Abstract: As reflector antennas continue to evolve towards higher gain and performance in the high-frequency range, the constraints posed by their structure and electromagnetic uncertainty on electrical properties like antenna gain and pointing accuracy are becoming increasingly evident, which significantly restricts the enhancement of reflector antennas' detection range and pointing accuracy. In this paper reflector antennas are taken as the object, an electromechanical coupling model is established for the structural uncertainty of reflector antennas. Based on interval analysis method, the directional pattern expression under the uncertainty of the main reflection surface shape is provided. Finally, the influence mechanism of feed source and main reflector uncertainty on antenna gain, pointing direction and other performance is discussed through an example of a 110 m antenna design model. The results show that the uncertainty of the feed source position has a greater impact on the sidelobe level and gain loss of the antenna than the uncertainty of the feed source pointing direction. The uncertainty of the inner ring panel shape of the main reflector has a greater impact on the electrical performance than that of the outer ring panel.