The invention discloses a single-satellite interference source positioning method based on a satellite-borne multi-wave-beam antenna. The method comprises the following steps that an antenna directional pattern model of each wave beam of the satellite-borne multi-wave-beam antenna is built, the antenna gain is correlated with the geographical position, and an antenna directional pattern geographical model is constructed; a ground station receives satellite transfer signals and carries out real-time monitoring, when the interference is monitored, the main interfered wave beams and adjacent common-frequency wave beams are determined, in addition, the interference signal parameters are cognized, the signal intensity of the interference signals in other adjacent common-frequency wave beams is measured according to the cognizing results, and the space distribution of the interference signal intensity in multi-wave-beam environment is obtained; a positioning equation set formed by the interference source position, the interference signal intensity and the antenna directional pattern gain function is built through combining the space distribution of the interference signal intensity and the antenna directional pattern geographical model, and the interference source positioning result is obtained. When the single-satellite interference source positioning method provided by the invention is adopted, the additional addition of satellite-borne equipment is not needed, the realization is simple, and in addition, the positioning precision is higher.