The invention relates to the technical field of antennas, and discloses a broadband feed source antenna based on asymmetric feed, which is characterized by comprising a waveguide tube, a horn is arranged at one end of the waveguide tube, a short circuit plate is arranged at the other end of the waveguide tube, and four groups of feed structures are arranged on the waveguide tube. The four groups of feed structures are arranged on the outer side wall of the waveguide tube in an annular array mode, each feed structure comprises a feed end and a conical probe, the conical probes are arranged in the waveguide tube and play a role in disturbing an electromagnetic field in the waveguide tube so that the electromagnetic field can excite a needed field, meanwhile, the conical structures of the conical probes can effectively broaden the matching bandwidth at the feed position, the broadband performance is thus achieved, and due to the fact that in the axial direction of the conical probe, the amplitude phases of electric fields on all surface points are different, the design of the conical probe with the gradually-changed size is adopted, and the matching bandwidth of corresponding ports can be independently widened; uniform-amplitude and anti-phase signals are fed into the feed structures opposite in position, so that the two conical probes opposite in position excite a co-polarization field in the waveguide tube.